Version 2.9.0-21.0.dev

Merge commit '06cb010247fb9163db673ba2fd0b338ad6caafb8' into dev
diff --git a/tools/VERSION b/tools/VERSION
index 186c1b0..b8eb434 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -29,11 +29,11 @@
 #  * Deprecating an old ABI version:
 #     - increase OLDEST_SUPPORTED_ABI_VERSION to the version that is supported.
 #
-CHANNEL be
+CHANNEL dev
 MAJOR 2
 MINOR 9
 PATCH 0
-PRERELEASE 0
+PRERELEASE 21
 PRERELEASE_PATCH 0
 ABI_VERSION 38
 OLDEST_SUPPORTED_ABI_VERSION 38