diff --git a/README.md b/README.md
index 619ce17..a4a0a86 100644
--- a/README.md
+++ b/README.md
@@ -1446,6 +1446,11 @@ This sketch demonstrates the use of the Catena FSM class to implement the `Turns
 
 ## Release History
 
+- HEAD includes the following changes
+
+  - fix [#319](https://github.com/mcci-catena/Catena-Arduino-Platform/issues/319): accomodate missing two-arg `UsbSerial::begin()` (v0.21.3-pre1).
+  - fix [#321](https://github.com/mcci-catena/Catena-Arduino-Platform/issues/321): add 24-bit float encoding support (v0.22.0-pre1).
+
 - v0.21.2 includes the following changes, non breaking, all bug fixes.
 
   - Check SessionState for validity when fetching ABP info ([#312](https://github.com/mcci-catena/Catena-Arduino-Platform/issues/312), `v0.21.2-pre1`).
diff --git a/src/CatenaBase.h b/src/CatenaBase.h
index 611a167..889600a 100644
--- a/src/CatenaBase.h
+++ b/src/CatenaBase.h
@@ -57,7 +57,7 @@ Copyright notice:
         (((major) << 24u) | ((minor) << 16u) | ((patch) << 8u) | (local))
 
 #define CATENA_ARDUINO_PLATFORM_VERSION \
-        CATENA_ARDUINO_PLATFORM_VERSION_CALC(0, 21, 3, 1) /* v0.21.3-1 */
+        CATENA_ARDUINO_PLATFORM_VERSION_CALC(0, 22, 0, 1) /* v0.22.0-pre1 */
 
 #define CATENA_ARDUINO_PLATFORM_VERSION_GET_MAJOR(v)    \
         (((v) >> 24u) & 0xFFu)