diff --git a/CHANGELOG.md b/CHANGELOG.md
index 935037d7033..6627ec07a71 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Dependency `esp-idf-sys` now re-exported as `esp_idf_hal::sys`
 * Breaking change: `delay::Delay` struct extended with configurable threshold
 * Breaking change: `task::wait_any_notification` removed; `task::notify` renamed to `task::notify_and_yield`; new function - `task::notify` - that notifies a task without automatically yielding to the notified task if it is a higher priority than the currently interrupted one
+* Deprecated: Using ESP-IDF 4.3 is now deprecated and all special cfg flags will be removed in the next release
 
 ## [0.41.2] - 2023-06-21
 
diff --git a/src/i2c.rs b/src/i2c.rs
index f8452d972bb..c070334476e 100644
--- a/src/i2c.rs
+++ b/src/i2c.rs
@@ -456,6 +456,9 @@ impl<'d> I2cSlaveDriver<'d> {
         };
 
         #[cfg(esp_idf_version = "4.3")]
+        #[deprecated(
+            note = "Using ESP-IDF 4.3 is untested, please upgrade to 4.4 or newer. Support will be removed in the next major release."
+        )]
         let sys_config = i2c_config_t {
             mode: i2c_mode_t_I2C_MODE_SLAVE,
             sda_io_num: pins.sda.pin(),
diff --git a/src/interrupt.rs b/src/interrupt.rs
index ffdf5ca5dad..96831bc282e 100644
--- a/src/interrupt.rs
+++ b/src/interrupt.rs
@@ -185,6 +185,9 @@ fn enter(_cs: &IsrCriticalSection) {
 #[link_section = ".iram1.interrupt_enter"]
 fn enter(cs: &IsrCriticalSection) {
     #[cfg(esp_idf_version = "4.3")]
+    #[deprecated(
+        note = "Using ESP-IDF 4.3 is untested, please upgrade to 4.4 or newer. Support will be removed in the next major release."
+    )]
     unsafe {
         vPortEnterCritical(cs.0.get());
     }
diff --git a/src/spi.rs b/src/spi.rs
index 3d8a45bf3e8..41de51f050d 100644
--- a/src/spi.rs
+++ b/src/spi.rs
@@ -431,6 +431,9 @@ impl<'d> SpiDriver<'d> {
 
         #[allow(clippy::needless_update)]
         #[cfg(esp_idf_version = "4.3")]
+        #[deprecated(
+            note = "Using ESP-IDF 4.3 is untested, please upgrade to 4.4 or newer. Support will be removed in the next major release."
+        )]
         let bus_config = spi_bus_config_t {
             flags: SPICOMMON_BUSFLAG_MASTER,
             sclk_io_num: sclk.pin(),
diff --git a/src/task.rs b/src/task.rs
index 21be2195c20..f6a9002ad3b 100644
--- a/src/task.rs
+++ b/src/task.rs
@@ -107,6 +107,9 @@ pub fn wait_notification(timeout: TickType_t) -> Option<u32> {
     let mut notification = 0_u32;
 
     #[cfg(esp_idf_version = "4.3")]
+    #[deprecated(
+        note = "Using ESP-IDF 4.3 is untested, please upgrade to 4.4 or newer. Support will be removed in the next major release."
+    )]
     let notified = unsafe { xTaskNotifyWait(0, u32::MAX, &mut notification, timeout) } != 0;
 
     #[cfg(not(esp_idf_version = "4.3"))]
@@ -145,6 +148,9 @@ pub unsafe fn notify(task: TaskHandle_t, notification: u32) -> (bool, bool) {
         let mut higher_prio_task_woken: BaseType_t = Default::default();
 
         #[cfg(esp_idf_version = "4.3")]
+        #[deprecated(
+            note = "Using ESP-IDF 4.3 is untested, please upgrade to 4.4 or newer. Support will be removed in the next major release."
+        )]
         let notified = xTaskGenericNotifyFromISR(
             task,
             notification,
@@ -166,6 +172,9 @@ pub unsafe fn notify(task: TaskHandle_t, notification: u32) -> (bool, bool) {
         (notified, higher_prio_task_woken)
     } else {
         #[cfg(esp_idf_version = "4.3")]
+        #[deprecated(
+            note = "Using ESP-IDF 4.3 is untested, please upgrade to 4.4 or newer. Support will be removed in the next major release."
+        )]
         let notified =
             xTaskGenericNotify(task, notification, eNotifyAction_eSetBits, ptr::null_mut());