diff --git a/.credo.exs b/.credo.exs
index aa56add9..436e20d5 100644
--- a/.credo.exs
+++ b/.credo.exs
@@ -104,7 +104,7 @@
           {Credo.Check.Readability.ParenthesesInCondition, []},
           {Credo.Check.Readability.ParenthesesOnZeroArityDefs, [parens: true]},
           {Credo.Check.Readability.PipeIntoAnonymousFunctions, []},
-          {Credo.Check.Readability.PredicateFunctionNames, []},
+          {Credo.Check.Readability.PredicateFunctionNames, false},
           {Credo.Check.Readability.PreferImplicitTry, []},
           {Credo.Check.Readability.RedundantBlankLines, []},
           {Credo.Check.Readability.Semicolons, []},
diff --git a/insights/mix.lock b/insights/mix.lock
index 4334edfb..0c8f5f82 100644
--- a/insights/mix.lock
+++ b/insights/mix.lock
@@ -4,8 +4,8 @@
   "cowboy": {:hex, :cowboy, "2.9.0", "865dd8b6607e14cf03282e10e934023a1bd8be6f6bacf921a7e2a96d800cd452", [:make, :rebar3], [{:cowlib, "2.11.0", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "1.8.0", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm", "2c729f934b4e1aa149aff882f57c6372c15399a20d54f65c8d67bef583021bde"},
   "cowboy_telemetry": {:hex, :cowboy_telemetry, "0.4.0", "f239f68b588efa7707abce16a84d0d2acf3a0f50571f8bb7f56a15865aae820c", [:rebar3], [{:cowboy, "~> 2.7", [hex: :cowboy, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "7d98bac1ee4565d31b62d59f8823dfd8356a169e7fcbb83831b8a5397404c9de"},
   "cowlib": {:hex, :cowlib, "2.11.0", "0b9ff9c346629256c42ebe1eeb769a83c6cb771a6ee5960bd110ab0b9b872063", [:make, :rebar3], [], "hexpm", "2b3e9da0b21c4565751a6d4901c20d1b4cc25cbb7fd50d91d2ab6dd287bc86a9"},
-  "db_connection": {:hex, :db_connection, "2.4.1", "6411f6e23f1a8b68a82fa3a36366d4881f21f47fc79a9efb8c615e62050219da", [:mix], [{:connection, "~> 1.0", [hex: :connection, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "ea36d226ec5999781a9a8ad64e5d8c4454ecedc7a4d643e4832bf08efca01f00"},
-  "decimal": {:hex, :decimal, "2.0.0", "a78296e617b0f5dd4c6caf57c714431347912ffb1d0842e998e9792b5642d697", [:mix], [], "hexpm", "34666e9c55dea81013e77d9d87370fe6cb6291d1ef32f46a1600230b1d44f577"},
+  "db_connection": {:hex, :db_connection, "2.5.0", "bb6d4f30d35ded97b29fe80d8bd6f928a1912ca1ff110831edcd238a1973652c", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "c92d5ba26cd69ead1ff7582dbb860adeedfff39774105a4f1c92cbb654b55aa2"},
+  "decimal": {:hex, :decimal, "2.1.1", "5611dca5d4b2c3dd497dec8f68751f1f1a54755e8ed2a966c2633cf885973ad6", [:mix], [], "hexpm", "53cfe5f497ed0e7771ae1a475575603d77425099ba5faef9394932b35020ffcc"},
   "ecto": {:hex, :ecto, "3.7.1", "a20598862351b29f80f285b21ec5297da1181c0442687f9b8329f0445d228892", [:mix], [{:decimal, "~> 1.6 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "d36e5b39fc479e654cffd4dbe1865d9716e4a9b6311faff799b6f90ab81b8638"},
   "ecto_sql": {:hex, :ecto_sql, "3.7.1", "8de624ef50b2a8540252d8c60506379fbbc2707be1606853df371cf53df5d053", [:mix], [{:db_connection, "~> 2.2", [hex: :db_connection, repo: "hexpm", optional: false]}, {:ecto, "~> 3.7.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:myxql, "~> 0.4.0 or ~> 0.5.0", [hex: :myxql, repo: "hexpm", optional: true]}, {:postgrex, "~> 0.15.0 or ~> 1.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:tds, "~> 2.1.1 or ~> 2.2", [hex: :tds, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4.0 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "2b42a32e2ce92f64aba5c88617891ab3b0ba34f3f3a503fa20009eae1a401c81"},
   "esbuild": {:hex, :esbuild, "0.4.0", "9f17db148aead4cf1e6e6a584214357287a93407b5fb51a031f122b61385d4c2", [:mix], [{:castore, ">= 0.0.0", [hex: :castore, repo: "hexpm", optional: false]}], "hexpm", "b61e4e6b92ffe45e4ee4755a22de6211a67c67987dc02afb35a425a0add1d447"},
diff --git a/lib/mongo.ex b/lib/mongo.ex
index c75fe250..ceb2c0ec 100644
--- a/lib/mongo.ex
+++ b/lib/mongo.ex
@@ -1571,7 +1571,10 @@ defmodule Mongo do
 
   def issue_command(topology_pid, cmd, :write, opts) do
     ## check, if retryable reads are enabled
-    opts = Mongo.retryable_writes(opts, acknowledged?(cmd[:writeConcerns]))
+    opts =
+      opts
+      |> Keyword.delete(:read_preferences)
+      |> Mongo.retryable_writes(acknowledged?(cmd[:writeConcerns]))
 
     case in_write_session(topology_pid, &exec_command_session(&1, cmd, &2), opts) do
       {:ok, doc} ->
diff --git a/lib/mongo/monitor.ex b/lib/mongo/monitor.ex
index d56fce6d..d80e984d 100644
--- a/lib/mongo/monitor.ex
+++ b/lib/mongo/monitor.ex
@@ -185,9 +185,22 @@ defmodule Mongo.Monitor do
 
   ##
   # Get a new server description from the server and send it to the Topology process.
+  # * Monitors MUST use a dedicated connection for RTT commands
+  # * Monitors MUST use the hello or legacy hello command to measure RTT
+  # * Why don't clients mark a server unknown when an RTT command fails?
   ##
-  defp update_server_description(%{mode: :streaming_mode} = state) do
-    state
+  defp update_server_description(%{topology_pid: topology_pid, address: address, mode: :streaming_mode} = state) do
+    case get_server_description(state) do
+      %{round_trip_time: round_trip_time} ->
+        ## debug info("Updating round_trip_time: #{inspect round_trip_time}")
+        Topology.update_rrt(topology_pid, address, round_trip_time)
+
+        %{state | round_trip_time: round_trip_time}
+
+      error ->
+        warning("Unable to round trip time because of #{inspect(error)}")
+        state
+    end
   end
 
   ##
diff --git a/lib/mongo/topology.ex b/lib/mongo/topology.ex
index d7f21d4e..1a133974 100644
--- a/lib/mongo/topology.ex
+++ b/lib/mongo/topology.ex
@@ -373,7 +373,7 @@ defmodule Mongo.Topology do
   # checkout a new session
   #
   def handle_call({:checkout_session, read_write_type, opts}, from, %{:topology => topology, :waiting_pids => waiting} = state) do
-    opts = merge_read_preferences(opts, state.opts)
+    opts = merge_read_preferences(read_write_type, opts, state.opts)
 
     case TopologyDescription.select_servers(topology, read_write_type, opts) do
       :empty ->
@@ -402,7 +402,7 @@ defmodule Mongo.Topology do
   end
 
   def handle_call({:select_server, read_write_type, opts}, from, %{:topology => topology, :waiting_pids => waiting} = state) do
-    opts = merge_read_preferences(opts, state.opts)
+    opts = merge_read_preferences(read_write_type, opts, state.opts)
 
     case TopologyDescription.select_servers(topology, read_write_type, opts) do
       :empty ->
@@ -586,7 +586,7 @@ defmodule Mongo.Topology do
     Enum.flat_map(state.topology.servers, fn {_, s} -> s.arbiters end)
   end
 
-  defp merge_read_preferences(opts, url_opts) do
+  defp merge_read_preferences(:read, opts, url_opts) do
     case Keyword.get(url_opts, :read_preference) do
       nil ->
         opts
@@ -596,6 +596,10 @@ defmodule Mongo.Topology do
     end
   end
 
+  defp merge_read_preferences(:write, opts, _url_opts) do
+    Keyword.delete(opts, :read_preference)
+  end
+
   defp merge_timeout(opts, default_ops) do
     case Keyword.get(default_ops, :timeout) do
       nil ->
diff --git a/lib/mongo/topology_description.ex b/lib/mongo/topology_description.ex
index 841472ec..bc40b798 100644
--- a/lib/mongo/topology_description.ex
+++ b/lib/mongo/topology_description.ex
@@ -109,8 +109,11 @@ defmodule Mongo.TopologyDescription do
       |> Enum.take_random(1)
 
     case addr do
-      [] -> :empty
-      [result] -> {:ok, {result, opts}}
+      [] ->
+        :empty
+
+      [result] ->
+        {:ok, {result, opts}}
     end
   end
 
diff --git a/mix.lock b/mix.lock
index 496e3055..163ce3b2 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,34 +1,16 @@
 %{
-  "benchee": {:hex, :benchee, "1.0.1", "66b211f9bfd84bd97e6d1beaddf8fc2312aaabe192f776e8931cb0c16f53a521", [:mix], [{:deep_merge, "~> 1.0", [hex: :deep_merge, repo: "hexpm", optional: false]}], "hexpm", "3ad58ae787e9c7c94dd7ceda3b587ec2c64604563e049b2a0e8baafae832addb"},
-  "bunt": {:hex, :bunt, "0.2.1", "e2d4792f7bc0ced7583ab54922808919518d0e57ee162901a16a1b6664ef3b14", [:mix], [], "hexpm", "a330bfb4245239787b15005e66ae6845c9cd524a288f0d141c148b02603777a5"},
-  "certifi": {:hex, :certifi, "2.5.1", "867ce347f7c7d78563450a18a6a28a8090331e77fa02380b4a21962a65d36ee5", [:rebar3], [{:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm", "805abd97539caf89ec6d4732c91e62ba9da0cda51ac462380bbd28ee697a8c42"},
-  "connection": {:hex, :connection, "1.1.0", "ff2a49c4b75b6fb3e674bfc5536451607270aac754ffd1bdfe175abe4a6d7a68", [:mix], [], "hexpm", "722c1eb0a418fbe91ba7bd59a47e28008a189d47e37e0e7bb85585a016b2869c"},
-  "credo": {:hex, :credo, "1.7.0", "6119bee47272e85995598ee04f2ebbed3e947678dee048d10b5feca139435f75", [:mix], [{:bunt, "~> 0.2.1", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2.8", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "6839fcf63d1f0d1c0f450abc8564a57c43d644077ab96f2934563e68b8a769d7"},
+  "bunt": {:hex, :bunt, "1.0.0", "081c2c665f086849e6d57900292b3a161727ab40431219529f13c4ddcf3e7a44", [:mix], [], "hexpm", "dc5f86aa08a5f6fa6b8096f0735c4e76d54ae5c9fa2c143e5a1fc7c1cd9bb6b5"},
+  "credo": {:hex, :credo, "1.7.4", "68ca5cf89071511c12fd9919eb84e388d231121988f6932756596195ccf7fd35", [:mix], [{:bunt, "~> 0.2.1 or ~> 1.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "9cf776d062c78bbe0f0de1ecaee183f18f2c3ec591326107989b054b7dddefc2"},
   "db_connection": {:hex, :db_connection, "2.6.0", "77d835c472b5b67fc4f29556dee74bf511bbafecdcaf98c27d27fa5918152086", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "c2f992d15725e721ec7fbc1189d4ecdb8afef76648c746a8e1cad35e3b8a35f3"},
   "decimal": {:hex, :decimal, "2.1.1", "5611dca5d4b2c3dd497dec8f68751f1f1a54755e8ed2a966c2633cf885973ad6", [:mix], [], "hexpm", "53cfe5f497ed0e7771ae1a475575603d77425099ba5faef9394932b35020ffcc"},
-  "deep_merge": {:hex, :deep_merge, "1.0.0", "b4aa1a0d1acac393bdf38b2291af38cb1d4a52806cf7a4906f718e1feb5ee961", [:mix], [], "hexpm", "ce708e5f094b9cd4e8f2be4f00d2f4250c4095be93f8cd6d018c753894885430"},
-  "dialyxir": {:hex, :dialyxir, "0.5.1", "b331b091720fd93e878137add264bac4f644e1ddae07a70bf7062c7862c4b952", [:mix], [], "hexpm", "6c32a70ed5d452c6650916555b1f96c79af5fc4bf286997f8b15f213de786f73"},
-  "earmark": {:hex, :earmark, "1.4.15", "2c7f924bf495ec1f65bd144b355d0949a05a254d0ec561740308a54946a67888", [:mix], [{:earmark_parser, ">= 1.4.13", [hex: :earmark_parser, repo: "hexpm", optional: false]}], "hexpm", "3b1209b85bc9f3586f370f7c363f6533788fb4e51db23aa79565875e7f9999ee"},
-  "earmark_parser": {:hex, :earmark_parser, "1.4.33", "3c3fd9673bb5dcc9edc28dd90f50c87ce506d1f71b70e3de69aa8154bc695d44", [:mix], [], "hexpm", "2d526833729b59b9fdb85785078697c72ac5e5066350663e5be6a1182da61b8f"},
-  "elixir_uuid": {:hex, :elixir_uuid, "1.2.0", "ff26e938f95830b1db152cb6e594d711c10c02c6391236900ddd070a6b01271d", [:mix], [], "hexpm"},
-  "erlex": {:hex, :erlex, "0.1.6", "c01c889363168d3fdd23f4211647d8a34c0f9a21ec726762312e08e083f3d47e", [:mix], [], "hexpm"},
-  "ex_doc": {:hex, :ex_doc, "0.30.6", "5f8b54854b240a2b55c9734c4b1d0dd7bdd41f71a095d42a70445c03cf05a281", [:mix], [{:earmark_parser, "~> 1.4.31", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1", [hex: :makeup_erlang, repo: "hexpm", optional: false]}], "hexpm", "bd48f2ddacf4e482c727f9293d9498e0881597eae6ddc3d9562bd7923375109f"},
-  "excoveralls": {:hex, :excoveralls, "0.12.1", "a553c59f6850d0aff3770e4729515762ba7c8e41eedde03208182a8dc9d0ce07", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "5c1f717066a299b1b732249e736c5da96bb4120d1e55dc2e6f442d251e18a812"},
-  "file_system": {:hex, :file_system, "0.2.10", "fb082005a9cd1711c05b5248710f8826b02d7d1784e7c3451f9c1231d4fc162d", [:mix], [], "hexpm", "41195edbfb562a593726eda3b3e8b103a309b733ad25f3d642ba49696bf715dc"},
-  "hackney": {:hex, :hackney, "1.15.2", "07e33c794f8f8964ee86cebec1a8ed88db5070e52e904b8f12209773c1036085", [:rebar3], [{:certifi, "2.5.1", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "6.0.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~>1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.5", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm", "e0100f8ef7d1124222c11ad362c857d3df7cb5f4204054f9f0f4a728666591fc"},
-  "idna": {:hex, :idna, "6.0.0", "689c46cbcdf3524c44d5f3dde8001f364cd7608a99556d8fbd8239a5798d4c10", [:rebar3], [{:unicode_util_compat, "0.4.1", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "4bdd305eb64e18b0273864920695cb18d7a2021f31a11b9c5fbcd9a253f936e2"},
+  "earmark_parser": {:hex, :earmark_parser, "1.4.39", "424642f8335b05bb9eb611aa1564c148a8ee35c9c8a8bba6e129d51a3e3c6769", [:mix], [], "hexpm", "06553a88d1f1846da9ef066b87b57c6f605552cfbe40d20bd8d59cc6bde41944"},
+  "ex_doc": {:hex, :ex_doc, "0.31.1", "8a2355ac42b1cc7b2379da9e40243f2670143721dd50748bf6c3b1184dae2089", [:mix], [{:earmark_parser, "~> 1.4.39", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.1", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1", [hex: :makeup_erlang, repo: "hexpm", optional: false]}], "hexpm", "3178c3a407c557d8343479e1ff117a96fd31bafe52a039079593fb0524ef61b0"},
+  "file_system": {:hex, :file_system, "1.0.0", "b689cc7dcee665f774de94b5a832e578bd7963c8e637ef940cd44327db7de2cd", [:mix], [], "hexpm", "6752092d66aec5a10e662aefeed8ddb9531d79db0bc145bb8c40325ca1d8536d"},
   "jason": {:hex, :jason, "1.4.1", "af1504e35f629ddcdd6addb3513c3853991f694921b1b9368b0bd32beb9f1b63", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "fbb01ecdfd565b56261302f7e1fcc27c4fb8f32d56eab74db621fc154604a7a1"},
-  "makeup": {:hex, :makeup, "1.1.0", "6b67c8bc2882a6b6a445859952a602afc1a41c2e08379ca057c0f525366fc3ca", [:mix], [{:nimble_parsec, "~> 1.2.2 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "0a45ed501f4a8897f580eabf99a2e5234ea3e75a4373c8a52824f6e873be57a6"},
+  "makeup": {:hex, :makeup, "1.1.1", "fa0bc768698053b2b3869fa8a62616501ff9d11a562f3ce39580d60860c3a55e", [:mix], [{:nimble_parsec, "~> 1.2.2 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "5dc62fbdd0de44de194898b6710692490be74baa02d9d108bc29f007783b0b48"},
   "makeup_elixir": {:hex, :makeup_elixir, "0.16.1", "cc9e3ca312f1cfeccc572b37a09980287e243648108384b97ff2b76e505c3555", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.2.3 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "e127a341ad1b209bd80f7bd1620a15693a9908ed780c3b763bccf7d200c767c6"},
-  "makeup_erlang": {:hex, :makeup_erlang, "0.1.2", "ad87296a092a46e03b7e9b0be7631ddcf64c790fa68a9ef5323b6cbb36affc72", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "f3f5a1ca93ce6e092d92b6d9c049bcda58a3b617a8d888f8e7231c85630e8108"},
-  "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm", "69b09adddc4f74a40716ae54d140f93beb0fb8978d8636eaded0c31b6f099f16"},
-  "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm", "f278585650aa581986264638ebf698f8bb19df297f66ad91b18910dfc6e19323"},
-  "nimble_parsec": {:hex, :nimble_parsec, "1.3.1", "2c54013ecf170e249e9291ed0a62e5832f70a476c61da16f6aac6dca0189f2af", [:mix], [], "hexpm", "2682e3c0b2eb58d90c6375fc0cc30bc7be06f365bf72608804fb9cffa5e1b167"},
-  "parse_trans": {:hex, :parse_trans, "3.3.0", "09765507a3c7590a784615cfd421d101aec25098d50b89d7aa1d66646bc571c1", [:rebar3], [], "hexpm", "17ef63abde837ad30680ea7f857dd9e7ced9476cdd7b0394432af4bfc241b960"},
+  "makeup_erlang": {:hex, :makeup_erlang, "0.1.4", "29563475afa9b8a2add1b7a9c8fb68d06ca7737648f28398e04461f008b69521", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "f4ed47ecda66de70dd817698a703f8816daa91272e7e45812469498614ae8b29"},
+  "nimble_parsec": {:hex, :nimble_parsec, "1.4.0", "51f9b613ea62cfa97b25ccc2c1b4216e81df970acd8e16e8d1bdc58fef21370d", [:mix], [], "hexpm", "9c565862810fb383e9838c1dd2d7d2c437b3d13b267414ba6af33e50d2d1cf28"},
   "patch": {:hex, :patch, "0.12.0", "2da8967d382bade20344a3e89d618bfba563b12d4ac93955468e830777f816b0", [:mix], [], "hexpm", "ffd0e9a7f2ad5054f37af84067ee88b1ad337308a1cb227e181e3967127b0235"},
-  "poolboy": {:hex, :poolboy, "1.5.2", "392b007a1693a64540cead79830443abf5762f5d30cf50bc95cb2c1aaafa006b", [:rebar3], [], "hexpm"},
-  "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.5", "6eaf7ad16cb568bb01753dbbd7a95ff8b91c7979482b95f38443fe2c8852a79b", [:make, :mix, :rebar3], [], "hexpm", "13104d7897e38ed7f044c4de953a6c28597d1c952075eb2e328bc6d6f2bfc496"},
-  "statistex": {:hex, :statistex, "1.0.0", "f3dc93f3c0c6c92e5f291704cf62b99b553253d7969e9a5fa713e5481cd858a5", [:mix], [], "hexpm", "ff9d8bee7035028ab4742ff52fc80a2aa35cece833cf5319009b52f1b5a86c27"},
   "telemetry": {:hex, :telemetry, "1.2.1", "68fdfe8d8f05a8428483a97d7aab2f268aaff24b49e0f599faa091f1d4e7f61c", [:rebar3], [], "hexpm", "dad9ce9d8effc621708f99eac538ef1cbe05d6a874dd741de2e689c47feafed5"},
-  "unicode_util_compat": {:hex, :unicode_util_compat, "0.4.1", "d869e4c68901dd9531385bb0c8c40444ebf624e60b6962d95952775cac5e90cd", [:rebar3], [], "hexpm", "1d1848c40487cdb0b30e8ed975e34e025860c02e419cb615d255849f3427439d"},
 }
diff --git a/test/mongo/read_preferences_test.exs b/test/mongo/read_preferences_test.exs
index 97efc434..bce157c5 100644
--- a/test/mongo/read_preferences_test.exs
+++ b/test/mongo/read_preferences_test.exs
@@ -86,10 +86,27 @@ defmodule Mongo.ReadPreferencesTest do
     prefs = %{
       mode: :secondary,
       max_staleness_ms: 120_000,
-      tags: [dc: "east", usage: "production"]
+      tags: [dc: "south", usage: "production"]
     }
 
     assert catch_exit(Mongo.find_one(top, coll, %{name: "Oskar"}, read_preference: prefs, checkout_timeout: 500))
     assert [:checkout_session | _xs] = EventCatcher.empty_selection_events(catcher) |> Enum.map(fn event -> event.action end)
   end
+
+  @tag :rs_required
+  test "find_one, using primary_preferred options" do
+    prefs = %{
+      mode: :primary_preferred
+    }
+
+    assert {:ok, top} = Mongo.start_link(database: "mongodb_test", seeds: ["127.0.0.1:27017"], read_preference: prefs, show_sensitive_data_on_connection_error: true)
+    Mongo.admin_command(top, configureFailPoint: "failCommand", mode: "off")
+
+    Mongo.insert_one(top, "dogs", %{name: "Greta"})
+    Mongo.insert_one(top, "dogs", %{name: "Tom"})
+    Mongo.insert_one(top, "dogs", %{name: "Gustav"})
+
+    assert :ok = Mongo.create_indexes(top, "dogs", [%{key: %{name: 1}, name: "name_index"}])
+    assert :ok = Mongo.create_indexes(top, "dogs", [%{key: %{name: 1}, name: "name_index"}], read_preference: prefs)
+  end
 end
diff --git a/test/mongo/url_parser_test.exs b/test/mongo/url_parser_test.exs
index b6115285..cdf5a332 100644
--- a/test/mongo/url_parser_test.exs
+++ b/test/mongo/url_parser_test.exs
@@ -186,6 +186,15 @@ defmodule Mongo.UrlParserTest do
                  "seed2.domain.com:27017"
                ]
              ]
+
+      assert UrlParser.parse_url(url: "mongodb://seed1.domain.com:27017,seed2.domain.com:27017/db_name?readPreference=primaryPreferred&maxStalenessSeconds=30") == [
+               database: "db_name",
+               read_preference: %{mode: :primary_preferred, max_staleness_ms: 30_000},
+               seeds: [
+                 "seed1.domain.com:27017",
+                 "seed2.domain.com:27017"
+               ]
+             ]
     end
 
     test "encoded user" do
diff --git a/test/support/collection_case.ex b/test/support/collection_case.ex
index df52e75e..cc098ca0 100644
--- a/test/support/collection_case.ex
+++ b/test/support/collection_case.ex
@@ -3,7 +3,6 @@ defmodule CollectionCase do
 
   use ExUnit.CaseTemplate
 
-  ## todo  , "127.0.0.1:27018", "127.0.0.1:27019"]
   @seeds ["127.0.0.1:27017"]
 
   setup_all do
diff --git a/test/support/test_connection.ex b/test/support/test_connection.ex
index 2f219664..acff3c2e 100644
--- a/test/support/test_connection.ex
+++ b/test/support/test_connection.ex
@@ -1,7 +1,6 @@
 defmodule Mongo.TestConnection do
   @moduledoc false
 
-  ## todo , "127.0.0.1:27018", "127.0.0.1:27019"]
   @seeds ["127.0.0.1:27017"]
 
   def connect() do