diff --git a/alembic/versions/49ef39173f83_add_components_json_field_to_jira_.py b/alembic/versions/49ef39173f83_add_components_json_field_to_jira_.py
new file mode 100644
index 0000000..c2f599d
--- /dev/null
+++ b/alembic/versions/49ef39173f83_add_components_json_field_to_jira_.py
@@ -0,0 +1,42 @@
+"""add components_json field to jira_fields table
+
+Revision ID: 49ef39173f83
+Revises: 54f755dbdb6f
+Create Date: 2024-12-18 17:01:39.676895
+
+"""
+import logging
+
+import sqlalchemy as sa
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "49ef39173f83"
+down_revision = "54f755dbdb6f"
+branch_labels = None
+depends_on = None
+
+
+JIRA_FIELDS_TABLE_NAME = "jira_fields"
+
+
+def upgrade(log: logging.Logger, table_names: set[str]) -> None:
+    if JIRA_FIELDS_TABLE_NAME not in table_names:
+        log.info(f"No {JIRA_FIELDS_TABLE_NAME} table; nothing to do")
+        return
+    log.info("Add 'components_json'")
+
+    op.add_column(
+        JIRA_FIELDS_TABLE_NAME,
+        sa.Column("components_json", sa.JSON(), nullable=True),
+    )
+
+
+def downgrade(log: logging.Logger, table_names: set[str]) -> None:
+    if JIRA_FIELDS_TABLE_NAME not in table_names:
+        log.info(f"No {JIRA_FIELDS_TABLE_NAME} table; nothing to do")
+        return
+
+    log.info("Drop 'components_json'")
+    op.drop_column(JIRA_FIELDS_TABLE_NAME, "components_json")
diff --git a/src/narrativelog/create_tables.py b/src/narrativelog/create_tables.py
index 9ed05c0..5b95d57 100644
--- a/src/narrativelog/create_tables.py
+++ b/src/narrativelog/create_tables.py
@@ -8,7 +8,7 @@
 
 import sqlalchemy as sa
 import sqlalchemy.types as saty
-from sqlalchemy.dialects.postgresql import UUID
+from sqlalchemy.dialects.postgresql import JSONB, UUID
 
 # Length of the site_id field.
 SITE_ID_LEN = 16
@@ -60,8 +60,14 @@ def create_message_table(metadata: sa.MetaData) -> sa.Table:
         sa.Column("date_invalidated", saty.DateTime(), nullable=True),
         sa.Column("parent_id", UUID(as_uuid=True), nullable=True),
         # Added 2022-07-19
+        # 'systems' field is deprecated and will be removed in v1.0.0.
+        # Please use 'components_json' instead
         sa.Column("systems", saty.ARRAY(sa.Text), nullable=True),
+        # 'subsystems' field is deprecated and will be removed in v1.0.0.
+        # Please use 'components_json' instead
         sa.Column("subsystems", saty.ARRAY(sa.Text), nullable=True),
+        # 'cscs' field is deprecated and will be removed in v1.0.0.
+        # Please use 'components_json' instead
         sa.Column("cscs", saty.ARRAY(sa.Text), nullable=True),
         # Added 2022-07-37
         sa.Column("date_end", saty.DateTime(), nullable=True),
@@ -110,10 +116,18 @@ def create_jira_fields_table(metadata: sa.MetaData) -> sa.Table:
         sa.Column(
             "id", UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
         ),
+        # Added 2024-12-16
+        sa.Column("components_json", JSONB, nullable=True),
+        # 'components' field is deprecated and will be removed in v1.0.0.
+        # Please use 'components_json' instead
         sa.Column("components", saty.ARRAY(sa.Text), nullable=True),
+        # 'primary_software_components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_json' instead
         sa.Column(
             "primary_software_components", saty.ARRAY(sa.Text), nullable=True
         ),
+        # 'primary_hardware_components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_json' instead
         sa.Column(
             "primary_hardware_components", saty.ARRAY(sa.Text), nullable=True
         ),
diff --git a/src/narrativelog/main.py b/src/narrativelog/main.py
index c5931fc..7b7a56e 100644
--- a/src/narrativelog/main.py
+++ b/src/narrativelog/main.py
@@ -10,6 +10,7 @@
     find_messages,
     get_configuration,
     get_message,
+    get_version,
 )
 
 app = fastapi.FastAPI()
@@ -27,6 +28,7 @@
 subapp.include_router(find_messages.router)
 subapp.include_router(get_configuration.router)
 subapp.include_router(get_message.router)
+subapp.include_router(get_version.router)
 
 
 @subapp.get("/", response_class=fastapi.responses.HTMLResponse)
diff --git a/src/narrativelog/message.py b/src/narrativelog/message.py
index d009a4e..1bc3c83 100644
--- a/src/narrativelog/message.py
+++ b/src/narrativelog/message.py
@@ -5,6 +5,8 @@
 
 from pydantic import BaseModel, Field
 
+from .utils import JIRA_OBS_SYSTEMS_HIERARCHY_MARKDOWN_LINK
+
 
 class Message(BaseModel):
     id: uuid.UUID = Field(title="Message ID: a UUID that is the primary key.")
@@ -46,13 +48,21 @@ class Message(BaseModel):
     )
     # Added 2022-07-19
     systems: None | list[str] = Field(
-        title="Zero or more system names.",
+        title="Zero or more system names. "
+        "This field is deprecated and will be removed in v1.0.0. "
+        "Please use 'components_json' instead.",
+    )
+    subsystems: None | list[str] = Field(
+        title="Zero or more subsystem names. "
+        "This field is deprecated and will be removed in v1.0.0. "
+        "Please use 'components_json' instead.",
     )
-    subsystems: None | list[str] = Field(title="Zero or more subsystem names.")
     cscs: None | list[str] = Field(
         title="Zero or more CSCs names. "
         "Each entry should be in the form 'name' or 'name:index', "
-        "where 'name' is the SAL component name and 'index' is the SAL index."
+        "where 'name' is the SAL component name and 'index' is the SAL index. "
+        "This field is deprecated and will be removed in v1.0.0. "
+        "Please use 'components_json' instead.",
     )
     # Added 2022-07-27
     date_end: None | datetime.datetime = Field(
@@ -61,15 +71,21 @@ class Message(BaseModel):
     # Added 2023-08-10
     components: None | list[str] = Field(
         title="Zero or more component names. "
-        "Each entry should be a valid component name entry on the OBS jira project.",
+        "Each entry should be a valid component name entry on the OBS jira project. "
+        "This field is deprecated and will be removed in v1.0.0. "
+        "Please use 'components_json' instead.",
     )
     primary_software_components: None | list[str] = Field(
         title="Zero or more primary software component names. "
-        "Each entry should be a valid component name entry on the OBS jira project.",
+        "Each entry should be a valid component name entry on the OBS jira project. "
+        "This field is deprecated and will be removed in v1.0.0. "
+        "Please use 'components_json' instead.",
     )
     primary_hardware_components: None | list[str] = Field(
         title="Zero or more primary hardware component names. "
-        "Each entry should be a valid component name entry on the OBS jira project.",
+        "Each entry should be a valid component name entry on the OBS jira project. "
+        "This field is deprecated and will be removed in v1.0.0. "
+        "Please use 'components_json' instead.",
     )
     # Added 2023-10-24
     category: None | str = Field(
@@ -78,6 +94,30 @@ class Message(BaseModel):
     time_lost_type: None | str = Field(
         title="Type of time lost.",
     )
+    # Added 2024-12-16
+    components_json: None | dict = Field(
+        default_factory=dict,
+        title="""
+JSON representation of systems, subsystems and components hierarchy
+ on the OBS jira project. An example of a valid payload is:
+
+    {
+        "name": "AuxTel",
+        "children": [
+            {
+                "name": "Dome",
+                "children": [
+                    {
+                        "name": "AT Azimuth Drives"
+                    }
+                ]
+            }
+        ]
+    }
+
+For a full list of valid systems, subsystems and components please refer to: """
+        f"""{JIRA_OBS_SYSTEMS_HIERARCHY_MARKDOWN_LINK}.""",
+    )
 
     class Config:
         orm_mode = True
@@ -85,9 +125,16 @@ class Config:
 
 
 JIRA_FIELDS = (
+    # 'components' field is deprecated and will be removed in v1.0.0.
+    # Please use 'components_json' instead
     "components",
+    # 'primary_software_components' field is deprecated
+    #  and will be removed in v1.0.0. Please use 'components_json' instead
     "primary_software_components",
+    # 'primary_hardware_components' field is deprecated
+    #  and will be removed in v1.0.0. Please use 'components_json' instead
     "primary_hardware_components",
+    "components_json",
 )
 MESSAGE_FIELDS = tuple(
     set(Message.schema()["properties"].keys()) - set(JIRA_FIELDS)
diff --git a/src/narrativelog/routers/add_message.py b/src/narrativelog/routers/add_message.py
index 74c41c7..948a722 100644
--- a/src/narrativelog/routers/add_message.py
+++ b/src/narrativelog/routers/add_message.py
@@ -9,6 +9,7 @@
 
 from ..message import Message
 from ..shared_state import SharedState, get_shared_state
+from ..utils import JIRA_OBS_SYSTEMS_HIERARCHY_MARKDOWN_LINK
 from .normalize_tags import TAG_DESCRIPTION, normalize_tags
 
 router = fastapi.APIRouter()
@@ -41,37 +42,73 @@ async def add_message(
     systems: None
     | list[str] = fastapi.Body(
         default=None,
-        description="Zero or more systems to which the message applies.",
+        description="Zero or more systems to which the message applies. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
     ),
     subsystems: None
     | list[str] = fastapi.Body(
         default=None,
-        description="Zero or more subsystems to which the message applies",
+        description="Zero or more subsystems to which the message applies. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
     ),
     cscs: None
     | list[str] = fastapi.Body(
         default=None,
         description="Zero or more CSCs to which the message applies. "
         "Each entry should be in the form 'name' or 'name:index', "
-        "where 'name' is the SAL component name and 'index' is the SAL index.",
+        "where 'name' is the SAL component name and 'index' is the SAL index. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
     ),
     components: None
     | list[str] = fastapi.Body(
         default=None,
         description="Zero or more components to which the message applies. "
-        "Each entry should be a valid component name entry on the OBS jira project.",
+        "Each entry should be a valid component name entry on the OBS jira project. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
     ),
     primary_software_components: None
     | list[str] = fastapi.Body(
         default=None,
         description="Primary software components to which the message applies. "
-        "Each entry should be a valid component name entry on the OBS jira project.",
+        "Each entry should be a valid component name entry on the OBS jira project. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
     ),
     primary_hardware_components: None
     | list[str] = fastapi.Body(
         default=None,
         description="Primary hardware components to which the message applies. "
-        "Each entry should be a valid component name entry on the OBS jira project.",
+        "Each entry should be a valid component name entry on the OBS jira project. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
+    ),
+    components_json: None
+    | dict = fastapi.Body(
+        default=None,
+        description="""
+JSON representation of systems, subsystems and components hierarchy
+ on the OBS jira project. An example of a valid payload is:
+
+    {
+        "name": "AuxTel",
+        "children": [
+            {
+                "name": "Dome",
+                "children": [
+                    {
+                        "name": "AT Azimuth Drives"
+                    }
+                ]
+            }
+        ]
+    }
+
+For a full list of valid systems, subsystems and components please refer to: """
+        f"""{JIRA_OBS_SYSTEMS_HIERARCHY_MARKDOWN_LINK}.""",
     ),
     urls: list[str] = fastapi.Body(
         default=[],
@@ -147,8 +184,14 @@ async def add_message(
                 user_agent=user_agent,
                 is_human=is_human,
                 date_added=curr_tai.tai.datetime,
+                # 'systems' field is deprecated and will be removed in v1.0.0.
+                #  Please use 'components_json' instead
                 systems=systems,
+                # 'subsystems' field is deprecated and will be removed in v1.0.0.
+                #  Please use 'components_json' instead
                 subsystems=subsystems,
+                # 'cscs' field is deprecated and will be removed in v1.0.0.
+                #  Please use 'components_json' instead
                 cscs=cscs,
                 category=category,
                 time_lost_type=time_lost_type,
@@ -166,17 +209,33 @@ async def add_message(
         if any(
             field is not None
             for field in (
+                # 'components' field is deprecated and will be removed in v1.0.0.
+                #  Please use 'components_json' instead
                 components,
+                # 'primary_software_components' field is deprecated
+                #  and will be removed in v1.0.0. Please use 'components_json' instead
                 primary_software_components,
+                # 'primary_hardware_components' field is deprecated
+                #  and will be removed in v1.0.0. Please use 'components_json' instead
                 primary_hardware_components,
+                components_json,
             )
         ):
             result_jira_fields = await connection.execute(
                 jira_fields_table.insert()
                 .values(
+                    # 'components' field is deprecated and will be removed in v1.0.0.
+                    #  Please use 'components_json' instead
                     components=components,
+                    # 'primary_software_components' field is deprecated
+                    #  and will be removed in v1.0.0.
+                    #  Please use 'components_json' instead
                     primary_software_components=primary_software_components,
+                    # 'primary_hardware_components' field is deprecated
+                    #  and will be removed in v1.0.0.
+                    #  Please use 'components_json' instead
                     primary_hardware_components=primary_hardware_components,
+                    components_json=components_json,
                     message_id=row_message.id,
                 )
                 .returning(sa.literal_column("*"))
diff --git a/src/narrativelog/routers/edit_message.py b/src/narrativelog/routers/edit_message.py
index a1efe7c..c9a1e7e 100644
--- a/src/narrativelog/routers/edit_message.py
+++ b/src/narrativelog/routers/edit_message.py
@@ -44,13 +44,17 @@ async def edit_message(
     | list[str] = fastapi.Body(
         default=None,
         description="Zero or more systems to which the message applied. "
-        "If specified, replaces all existing entries.",
+        "If specified, replaces all existing entries."
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
     ),
     subsystems: None
     | list[str] = fastapi.Body(
         default=None,
         description="Zero or more subsystems to which the message applies. "
-        "If specified, replaces all existing entries.",
+        "If specified, replaces all existing entries."
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
     ),
     cscs: None
     | list[str] = fastapi.Body(
@@ -58,28 +62,49 @@ async def edit_message(
         description="Zero or more CSCs to which the message applies. "
         "Each entry should be in the form 'name' or 'name:index', "
         "where 'name' is the SAL component name and 'index' is the SAL index. "
-        "If specified, replaces all existing entries.",
+        "If specified, replaces all existing entries."
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
     ),
     components: None
     | list[str] = fastapi.Body(
         default=None,
         description="Zero or more components to which the message applies. "
         "Each entry should be a valid component name entry on the OBS jira project. "
-        "If specified, replaces all existing entries.",
+        "If specified, replaces all existing entries."
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
     ),
     primary_software_components: None
     | list[str] = fastapi.Body(
         default=None,
         description="Primary software components to which the message applies. "
         "Each entry should be a valid component name entry on the OBS jira project. "
-        "If specified, replaces all existing entries.",
+        "If specified, replaces all existing entries."
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
     ),
     primary_hardware_components: None
     | list[str] = fastapi.Body(
         default=None,
         description="Primary hardware components to which the message applies. "
         "Each entry should be a valid component name entry on the OBS jira project. "
-        "If specified, replaces all existing entries.",
+        "If specified, replaces all existing entries."
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_json' instead.",
+    ),
+    components_json: None
+    | dict = fastapi.Body(
+        default=None,
+        description="JSON representation of systems, subsystems and components "
+        "on the OBS jira project. An example of a valid payload is: "
+        '`{"systems": ["Simonyi", "AuxTel"], '
+        '{"subsystems": ["TMA", "Mount"], '
+        '{"components": ["MTMount CSC"]}`. '
+        "For a full list of valid systems, subsystems and components "
+        "please refer to: [Systems, Sub-Systems and Components Proposal "
+        "for the OBS Jira project](https://rubinobs.atlassian.net/wiki/spaces/LSSTCOM/"
+        "pages/53741849/Systems+Sub-Systems+and+Components+Proposal+for+JIRA)",
     ),
     urls: None
     | list[str] = fastapi.Body(
@@ -143,12 +168,25 @@ async def edit_message(
         "message_text",
         "level",
         "tags",
+        # 'systems' field is deprecated and will be removed in v1.0.0.
+        #  Please use 'components_json' instead
         "systems",
+        # 'subsystems' field is deprecated and will be removed in v1.0.0.
+        #  Please use 'components_json' instead
         "subsystems",
+        # 'cscs' field is deprecated and will be removed in v1.0.0.
+        #  Please use 'components_json' instead
         "cscs",
+        # 'components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_json' instead
         "components",
+        # 'primary_software_components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_json' instead
         "primary_software_components",
+        # 'primary_hardware_components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_json' instead
         "primary_hardware_components",
+        "components_json",
         "category",
         "time_lost_type",
         "urls",
@@ -165,9 +203,16 @@ async def edit_message(
             request_data[name] = value
 
     jira_update_params = {
+        # 'components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_json' instead
         "components",
+        # 'primary_software_components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_json' instead
         "primary_software_components",
+        # 'primary_hardware_components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_json' instead
         "primary_hardware_components",
+        "components_json",
     }
 
     async with state.narrativelog_db.engine.begin() as connection:
diff --git a/src/narrativelog/routers/find_messages.py b/src/narrativelog/routers/find_messages.py
index e345e88..64337bd 100644
--- a/src/narrativelog/routers/find_messages.py
+++ b/src/narrativelog/routers/find_messages.py
@@ -3,12 +3,14 @@
 import datetime
 import enum
 import http
+import json
 
 import fastapi
 import sqlalchemy as sa
 
 from ..message import MESSAGE_ORDER_BY_VALUES, Message
 from ..shared_state import SharedState, get_shared_state
+from ..utils import JIRA_OBS_SYSTEMS_HIERARCHY_MARKDOWN_LINK
 from .normalize_tags import TAG_DESCRIPTION, normalize_tags
 
 router = fastapi.APIRouter()
@@ -101,42 +103,54 @@ async def find_messages(
         default=None,
         description="System names or fragments of names. All messages "
         "with a system that matches any of these are included. "
-        "Repeat the parameter for each value.",
+        "Repeat the parameter for each value. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
     ),
     exclude_systems: None
     | list[str] = fastapi.Query(
         default=None,
         description="System names or fragments of names. All messages "
         "with a system that matches any of these are excluded. "
-        "Repeat the parameter for each value.",
+        "Repeat the parameter for each value. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
     ),
     subsystems: None
     | list[str] = fastapi.Query(
         default=None,
         description="Subsystem names or fragments of names. All messages "
         "with a subsystem that matches any of these are included. "
-        "Repeat the parameter for each value.",
+        "Repeat the parameter for each value. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
     ),
     exclude_subsystems: None
     | list[str] = fastapi.Query(
         default=None,
         description="Subsystem names or fragments of names. All messages "
         "with a subsystem that matches any of these are excluded. "
-        "Repeat the parameter for each value.",
+        "Repeat the parameter for each value. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
     ),
     cscs: None
     | list[str] = fastapi.Query(
         default=None,
         description="CSC names or fragments of CSC names, "
         "of which at least one must be present. "
-        "Repeat the parameter for each value.",
+        "Repeat the parameter for each value. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
     ),
     exclude_cscs: None
     | list[str] = fastapi.Query(
         default=None,
         description="CSC names or fragments of CSC names, "
         "of which all must be absent. "
-        "Repeat the parameter for each value.",
+        "Repeat the parameter for each value. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
     ),
     components: None
     | list[str] = fastapi.Query(
@@ -144,7 +158,9 @@ async def find_messages(
         description="Component names or fragments of names. All messages "
         "with a component that matches any of these are included. "
         "Repeat the parameter for each value. "
-        "Each entry should be a valid component name entry on the OBS jira project.",
+        "Each entry should be a valid component name entry on the OBS jira project. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
     ),
     exclude_components: None
     | list[str] = fastapi.Query(
@@ -152,7 +168,9 @@ async def find_messages(
         description="Component names or fragments of names. All messages "
         "with a component that matches any of these are excluded. "
         "Repeat the parameter for each value. "
-        "Each entry should be a valid component name entry on the OBS jira project.",
+        "Each entry should be a valid component name entry on the OBS jira project. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
     ),
     primary_software_components: None
     | list[str] = fastapi.Query(
@@ -160,7 +178,9 @@ async def find_messages(
         description="Primary software components names or fragments of names. "
         "All messages with a component that matches any of these are included. "
         "Repeat the parameter for each value. "
-        "Each entry should be a valid component name entry on the OBS jira project.",
+        "Each entry should be a valid component name entry on the OBS jira project. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
     ),
     exclude_primary_software_components: None
     | list[str] = fastapi.Query(
@@ -168,7 +188,9 @@ async def find_messages(
         description="Primary software components names or fragments of names. "
         "All messages with a component that matches any of these are excluded. "
         "Repeat the parameter for each value. "
-        "Each entry should be a valid component name entry on the OBS jira project.",
+        "Each entry should be a valid component name entry on the OBS jira project. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
     ),
     primary_hardware_components: None
     | list[str] = fastapi.Query(
@@ -176,14 +198,171 @@ async def find_messages(
         description="Primary hardware components names or fragments of names. "
         "All messages with a component that matches any of these are included. "
         "Repeat the parameter for each value. "
-        "Each entry should be a valid component name entry on the OBS jira project.",
+        "Each entry should be a valid component name entry on the OBS jira project. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
     ),
     exclude_primary_hardware_components: None
     | list[str] = fastapi.Query(
         default=None,
         description="Primary hardware components names or fragments of names. "
         "All messages with a component that matches any of these are excluded. "
-        "Repeat the parameter for each value.",
+        "Repeat the parameter for each value. "
+        "**This field is deprecated and will be removed in v1.0.0**. "
+        "Please use 'components_path' instead.",
+    ),
+    components_path: None
+    | list[str] = fastapi.Query(
+        default=None,
+        description="""
+List of strings with components structure in JSON format to include.
+ Matches all messages with at least a JSON path included in the "components_path" list.
+ Each element in the list is a JSON string as the object that represents the current
+ hierarchy of systems, subsystems and components on the OBS Jira project:
+ `System -> Subsystem -> Component`
+ (check """
+        f"""{JIRA_OBS_SYSTEMS_HIERARCHY_MARKDOWN_LINK}"""
+        """ for valid hierarchies).
+ E.g. Setting a "components_path" string (you can add multiple) to
+
+    {
+        "name": "AuxTel",
+        "children": [
+            {
+                "name": "Dome",
+                "children": [
+                    {
+                        "name": "AT Azimuth Drives"
+                    }
+                ]
+            }
+        ]
+    }
+
+will match all messages that have "AuxTel" as system AND
+ "Dome" as subsystem of "AuxTel" AND
+ "AT Azimuth Drives" as component of "Dome".
+ Note that setting "components_path" to
+
+    {
+        "name": "AuxTel",
+        "children": [
+            {
+                "name": "Dome"
+            },
+            {
+                "name": "Mount"
+            }
+        ]
+    }
+
+Is the same as setting it to
+
+    {
+        "name": "AuxTel",
+        "children": [
+            {
+                "name": "Mount"
+            },
+            {
+                "name": "Dome"
+            }
+        ]
+    }
+
+In other words, the order of the children is not important.
+ Also setting a `children` key as `[]` is the same as not defining it
+ (will be ignored). Furthermore setting a "components_path" string
+ to `{}` will have no effect and any invalid JSON will raise a 400 error.
+ Take in mind that values are case senstive.
+
+All defined JSON strings will be joined with an OR operator.
+ E.g. setting two "components_path" as
+
+    { "name": "AuxTel" }
+
+and
+
+    { "name": "Simonyi" }
+
+Will match all messages that have "AuxTel" OR "Simonyi" as system.""",
+    ),
+    exclude_components_path: None
+    | list[str] = fastapi.Query(
+        default=None,
+        description="""
+List of strings with components structure in JSON format to exclude.
+ Exclude all messages with at least a JSON path
+ included in the "exclude_components_path" list.
+ Each element in the list is a JSON string as the object that represents the current
+ hierarchy of systems, subsystems and components on the OBS Jira project:
+ `System -> Subsystem -> Component`
+ (check """
+        f"""{JIRA_OBS_SYSTEMS_HIERARCHY_MARKDOWN_LINK}"""
+        """ for valid hierarchies).
+ E.g. Setting a "exclude_components_path" string (you can add multiple) to
+
+    {
+        "name": "AuxTel",
+        "children": [
+            {
+                "name": "Dome",
+                "children": [
+                    {
+                        "name": "AT Azimuth Drives"
+                    }
+                ]
+            }
+        ]
+    }
+
+will exclude all messages that have "AuxTel" as system AND
+ "Dome" as subsystem of "AuxTel" AND
+ "AT Azimuth Drives" as component of "Dome".
+ Note that setting "exclude_components_path" to
+
+    {
+        "name": "AuxTel",
+        "children": [
+            {
+                "name": "Dome"
+            },
+            {
+                "name": "Mount"
+            }
+        ]
+    }
+
+Is the same as setting it to
+
+    {
+        "name": "AuxTel",
+        "children": [
+            {
+                "name": "Mount"
+            },
+            {
+                "name": "Dome"
+            }
+        ]
+    }
+
+In other words, the order of the children is not important.
+ Also setting a `children` key as `[]` is the same as not defining it
+ (will be ignored). Furthermore setting a "exclude_components_path" string
+ to `{}` will have no effect and any invalid JSON will raise a 400 error.
+ Take in mind that values are case senstive.
+
+All defined JSON strings will be joined with an OR operator.
+ E.g. setting two "exclude_components_path" as
+
+    { "name": "AuxTel" }
+
+and
+
+    { "name": "Simonyi" }
+
+Will exclude all messages that have "AuxTel" OR "Simonyi" as system.""",
     ),
     urls: None
     | list[str] = fastapi.Query(
@@ -299,18 +478,44 @@ async def find_messages(
         "max_level",
         "user_ids",
         "user_agents",
+        # 'systems' field is deprecated and will be removed in v1.0.0.
+        #  Please use 'components_path' instead
         "systems",
+        # 'exclude_systems' field is deprecated and will be removed in v1.0.0.
+        #  Please use 'components_path' instead
         "exclude_systems",
+        # 'subsystems' field is deprecated and will be removed in v1.0.0.
+        #  Please use 'components_path' instead
         "subsystems",
+        # 'exclude_subsystems' field is deprecated and will be removed in v1.0.0.
+        #  Please use 'components_path' instead
         "exclude_subsystems",
+        # 'cscs' field is deprecated and will be removed in v1.0.0.
+        #  Please use 'components_path' instead
         "cscs",
+        # 'exclude_cscs' field is deprecated and will be removed in v1.0.0.
+        #  Please use 'components_path' instead
         "exclude_cscs",
+        # 'components' field is deprecated and will be removed in v1.0.0.
+        #  Please use 'components_path' instead
         "components",
+        # 'exclude_components' field is deprecated and will be removed in v1.0.0.
+        #  Please use 'components_path' instead
         "exclude_components",
+        # 'primary_software_components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_path' instead
         "primary_software_components",
+        # 'exclude_primary_software_components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_path' instead
         "exclude_primary_software_components",
+        # 'primary_hardware_components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_path' instead
         "primary_hardware_components",
+        # 'exclude_primary_hardware_components' field is deprecated
+        #  and will be removed in v1.0.0. Please use 'components_path' instead
         "exclude_primary_hardware_components",
+        "components_path",
+        "exclude_components_path",
         "tags",
         "exclude_tags",
         "urls",
@@ -386,8 +591,14 @@ async def find_messages(
                     conditions.append(column == None)  # noqa
             elif key in {
                 "tags",
+                # 'systems' field is deprecated and will be removed in v1.0.0.
+                #  Please use 'components_path' instead
                 "systems",
+                # 'subsystems' field is deprecated and will be removed in v1.0.0.
+                #  Please use 'components_path' instead
                 "subsystems",
+                # 'cscs' field is deprecated and will be removed in v1.0.0.
+                #  Please use 'components_path' instead
                 "cscs",
                 "urls",
             }:
@@ -406,16 +617,28 @@ async def find_messages(
                 column = message_table.columns[key]
                 conditions.append(column.op("&&")(value))
             elif key in {
+                # 'components' field is deprecated and will be removed in v1.0.0.
+                #  Please use 'components_path' instead
                 "components",
+                # 'primary_software_components' field is deprecated
+                #  and will be removed in v1.0.0. Please use 'components_path' instead
                 "primary_software_components",
+                # 'primary_hardware_components' field is deprecated
+                #  and will be removed in v1.0.0. Please use 'components_path' instead
                 "primary_hardware_components",
             }:
                 column = jira_fields_table.columns[key]
                 conditions.append(column.op("&&")(value))
             elif key in {
                 "exclude_tags",
+                # 'exclude_systems' field is deprecated
+                #  and will be removed in v1.0.0. Please use 'components_path' instead
                 "exclude_systems",
+                # 'exclude_subsystems' field is deprecated
+                #  and will be removed in v1.0.0. Please use 'components_path' instead
                 "exclude_subsystems",
+                # 'exclude_cscs' field is deprecated
+                #  and will be removed in v1.0.0. Please use 'components_path' instead
                 "exclude_cscs",
             }:
                 # Value is a list; field name is the end of the key.
@@ -425,13 +648,49 @@ async def find_messages(
                 column = message_table.columns[column_name]
                 conditions.append(sa.sql.not_(column.op("&&")(value)))
             elif key in {
+                # 'exclude_components' field is deprecated
+                #  and will be removed in v1.0.0. Please use 'components_path' instead
                 "exclude_components",
+                # 'exclude_primary_software_components' field is deprecated
+                #  and will be removed in v1.0.0. Please use 'components_path' instead
                 "exclude_primary_software_components",
+                # 'exclude_primary_hardware_components' field is deprecated
+                #  and will be removed in v1.0.0. Please use 'components_path' instead
                 "exclude_primary_hardware_components",
             }:
                 column_name = key[8:]
                 column = jira_fields_table.columns[column_name]
                 conditions.append(sa.sql.not_(column.op("&&")(value)))
+            elif key in {"components_path"}:
+                column_name = "components_json"
+                column = jira_fields_table.columns[column_name]
+                individual_conditions = []
+                for path in value:
+                    try:
+                        parsed_value = json.loads(path)
+                    except json.JSONDecodeError as error:
+                        raise fastapi.HTTPException(
+                            status_code=http.HTTPStatus.BAD_REQUEST,
+                            detail=f"Invalid JSON in {key}: {error}",
+                        )
+                    individual_conditions.append(column.contains(parsed_value))
+                conditions.append(sa.sql.or_(*individual_conditions))
+            elif key in {"exclude_components_path"}:
+                column_name = "components_json"
+                column = jira_fields_table.columns[column_name]
+                individual_conditions = []
+                for path in value:
+                    try:
+                        parsed_value = json.loads(path)
+                    except json.JSONDecodeError as error:
+                        raise fastapi.HTTPException(
+                            status_code=http.HTTPStatus.BAD_REQUEST,
+                            detail=f"Invalid JSON in {key}: {error}",
+                        )
+                    individual_conditions.append(column.contains(parsed_value))
+                conditions.append(
+                    sa.sql.not_(sa.sql.or_(*individual_conditions))
+                )
             elif key in {
                 "site_ids",
                 "instruments",
diff --git a/src/narrativelog/routers/get_version.py b/src/narrativelog/routers/get_version.py
new file mode 100644
index 0000000..c40c348
--- /dev/null
+++ b/src/narrativelog/routers/get_version.py
@@ -0,0 +1,27 @@
+__all__ = ["get_version"]
+
+import fastapi
+import pydantic
+
+from .. import __version__
+from ..shared_state import SharedState, get_shared_state
+
+router = fastapi.APIRouter()
+
+
+class Version(pydantic.BaseModel):
+    version: str = pydantic.Field(title="Current version of the REST API.")
+
+    class Config:
+        orm_mode = True
+        from_attributes = True
+
+
+@router.get("/version", response_model=Version)
+@router.get("/version/", response_model=Version, include_in_schema=False)
+async def get_version(
+    state: SharedState = fastapi.Depends(get_shared_state),
+) -> Version:
+    """Get the current version of the package."""
+
+    return Version(version=__version__)
diff --git a/src/narrativelog/testutils.py b/src/narrativelog/testutils.py
index 4673cba..0ccf10d 100644
--- a/src/narrativelog/testutils.py
+++ b/src/narrativelog/testutils.py
@@ -366,6 +366,12 @@ def random_message() -> MessageDictT:
     elif random_value > 0.25:
         date_begin = random_date()
 
+    test_components_json = {
+        "systems": random_strings(TEST_SYSTEMS),
+        "subsystems": random_strings(TEST_SUBSYSTEMS),
+        "components": random_strings(TEST_COMPONENTS),
+    }
+
     message = dict(
         id=None,
         site_id=TEST_SITE_ID,
@@ -396,6 +402,8 @@ def random_message() -> MessageDictT:
         primary_hardware_components=random_strings(
             TEST_PRIMARY_HARDWARE_COMPONENTS
         ),
+        # Added 2024-12-16
+        components_json=test_components_json,
         # Added 2023-10-24
         category=random_str(nchar=CATEGORY_LEN),
         time_lost_type=random.choice(["fault", "weather"]),
@@ -502,11 +510,14 @@ async def create_test_database(
             pruned_message = message.copy()
             del pruned_message["is_valid"]
             # Do not insert "components",
-            # "primary_software_components", or "primary_hardware_components"
+            # "primary_software_components",
+            # "primary_hardware_components",
+            # or "components_json"
             # because they are in a separate table.
             del pruned_message["components"]
             del pruned_message["primary_software_components"]
             del pruned_message["primary_hardware_components"]
+            del pruned_message["components_json"]
 
             # Insert the message
             result_message = await connection.execute(
@@ -529,6 +540,7 @@ async def create_test_database(
                     primary_hardware_components=message[
                         "primary_hardware_components"
                     ],
+                    components_json=message["components_json"],
                     message_id=data_message.id,
                 )
                 .returning(literal_column("*"))
diff --git a/src/narrativelog/utils.py b/src/narrativelog/utils.py
new file mode 100644
index 0000000..32e4d0d
--- /dev/null
+++ b/src/narrativelog/utils.py
@@ -0,0 +1,7 @@
+__all__ = ["JIRA_OBS_SYSTEMS_HIERARCHY_MARKDOWN_LINK"]
+
+JIRA_OBS_SYSTEMS_HIERARCHY_MARKDOWN_LINK = (
+    "[Systems, Sub-Systems and Components Proposal for the OBS Jira project]"
+    "(https://rubinobs.atlassian.net/wiki/spaces/LSSTCOM/pages/53741849/"
+    "Systems+Sub-Systems+and+Components+Proposal+for+JIRA)"
+)
diff --git a/tests/test_add_message.py b/tests/test_add_message.py
index e2b051d..fc46f26 100644
--- a/tests/test_add_message.py
+++ b/tests/test_add_message.py
@@ -90,6 +90,13 @@ async def test_add_message(self) -> None:
             add_args_full["primary_hardware_components"] = random_strings(
                 TEST_PRIMARY_HARDWARE_COMPONENTS
             )
+
+            test_components_json = {
+                "systems": random_strings(TEST_SYSTEMS),
+                "subsystems": random_strings(TEST_SUBSYSTEMS),
+                "components": random_strings(TEST_COMPONENTS),
+            }
+            add_args_full["components_json"] = test_components_json
             add_args_full["category"] = "test"
             add_args_full["time_lost_type"] = random.choice(
                 ["fault", "weather"]
diff --git a/tests/test_edit_message.py b/tests/test_edit_message.py
index 1b0ea0c..3679a6d 100644
--- a/tests/test_edit_message.py
+++ b/tests/test_edit_message.py
@@ -85,6 +85,11 @@ async def test_edit_message(self) -> None:
                     "new primary_hardware_component 1",
                     "new primary_hardware_component 2",
                 ],
+                components_json={
+                    "systems": ["new system 1", "new system 2"],
+                    "subsystems": ["new subsystem 1", "new subsystem 2"],
+                    "components": ["new component 1", "new component 2"],
+                },
                 category="New category",
                 time_lost_type=random.choice(["fault", "weather"]),
                 date_begin="2024-01-01T00:00:00",
diff --git a/tests/test_find_messages.py b/tests/test_find_messages.py
index 11e9f38..3afe6da 100644
--- a/tests/test_find_messages.py
+++ b/tests/test_find_messages.py
@@ -1,6 +1,7 @@
 import collections.abc
 import http
 import itertools
+import json
 import random
 import typing
 import unittest
@@ -267,7 +268,15 @@ def test_collection(
                 )
 
             # exclude_key for collection arguments for arrays
-            for field in ("tags",):
+            for field in (
+                "tags",
+                "systems",
+                "subsystems",
+                "cscs",
+                "components",
+                "primary_software_components",
+                "primary_hardware_components",
+            ):
                 # Scramble the messages and use two field list values
                 # from the first message with at least two values
                 messages_to_search = random.sample(messages, len(messages))
@@ -333,6 +342,50 @@ def test_contains(
 
                 find_args_predicates.append(({field: value}, test_contains))
 
+            # "Contains" arguments for JSON fields: these specify a
+            # JSON path to match.
+            for field in ("components_json",):
+                # Scramble the messages and use the first
+                # message with at least a key with two values
+                messages_to_search = random.sample(messages, len(messages))
+                for message in messages_to_search:
+                    components_json = message[field]
+                    for key in components_json:
+                        if len(components_json[key]) >= 2:
+                            first_two_values = components_json[key][0:2]
+                            values = [(key, val) for val in first_two_values]
+                            path = json.dumps({key: first_two_values})
+                            break
+
+                @doc_str(f"{path!r} in message[{field!r}]")
+                def test_contains_path(
+                    message: MessageDictT,
+                    field: str = field,
+                    values: list[tuple[str, str]] = values,
+                ) -> bool:
+                    matches = [
+                        val in message[field][key] for key, val in values
+                    ]
+                    return any(matches)
+
+                def test_contains_exclude_path(
+                    message: MessageDictT,
+                    field: str = field,
+                    values: list[tuple[str, str]] = values,
+                ) -> bool:
+                    matches = [
+                        val in message[field][key] for key, val in values
+                    ]
+                    return not any(matches)
+
+                find_args_predicates += [
+                    ({"components_path": path}, test_contains_path),
+                    (
+                        {"exclude_components_path": path},
+                        test_contains_exclude_path,
+                    ),
+                ]
+
             # has_<field> arguments (for fields that may be null).
             for field in (
                 "date_begin",
@@ -451,7 +504,6 @@ def is_valid_predicate(message: MessageDictT) -> bool:
             fields = list(MESSAGE_FIELDS)
             str_fields = set(
                 (
-                    "instrument",
                     "message_text",
                     "level",
                     "user_id",