diff --git a/.buildconfig.yml b/.buildconfig.yml
index eb01ada486..ad9bd37938 100644
--- a/.buildconfig.yml
+++ b/.buildconfig.yml
@@ -1,4 +1,4 @@
-libraryVersion: 21.2.0
+libraryVersion: 21.2.1-TESTING1
 groupId: org.mozilla.telemetry
 projects:
   glean:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ab9f86ee30..012ee5c568 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,10 @@
 # Unreleased changes
 
-[Full changelog](https://github.com/mozilla/glean/compare/v21.2.0...master)
+[Full changelog](https://github.com/mozilla/glean/compare/v21.2.1-alpha.1...master)
+
+# v21.2.1-alpha.1 (2019-11-27)
+
+[Full changelog](https://github.com/mozilla/glean/compare/v21.2.0...21.2.1-alpha.1)
 
 # v21.2.0 (2019-11-21)
 
diff --git a/Cargo.lock b/Cargo.lock
index 6012f9da4c..e0841065d5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -297,7 +297,7 @@ dependencies = [
 
 [[package]]
 name = "glean-core"
-version = "21.2.0"
+version = "21.2.1-alpha.1"
 dependencies = [
  "bincode 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "chrono 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -320,12 +320,12 @@ dependencies = [
 
 [[package]]
 name = "glean-ffi"
-version = "21.2.0"
+version = "21.2.1-alpha.1"
 dependencies = [
  "android_logger 0.8.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "ffi-support 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "glean-core 21.2.0",
+ "glean-core 21.2.1-alpha.1",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "uuid 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/glean-core/Cargo.toml b/glean-core/Cargo.toml
index 05c2876b1b..7aa4b286b4 100644
--- a/glean-core/Cargo.toml
+++ b/glean-core/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "glean-core"
-version = "21.2.0"
+version = "21.2.1-alpha.1"
 authors = ["Jan-Erik Rediger <jrediger@mozilla.com>", "The Glean Team <glean-team@mozilla.com>"]
 description = "A modern Telemetry library"
 repository = "https://github.com/mozilla/glean"
diff --git a/glean-core/ffi/Cargo.toml b/glean-core/ffi/Cargo.toml
index edee1a7545..405e8643cc 100644
--- a/glean-core/ffi/Cargo.toml
+++ b/glean-core/ffi/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "glean-ffi"
-version = "21.2.0"
+version = "21.2.1-alpha.1"
 authors = ["Jan-Erik Rediger <jrediger@mozilla.com>", "The Glean Team <glean-team@mozilla.com>"]
 description = "FFI layer for Glean, a modern Telemetry library"
 repository = "https://github.com/mozilla/glean"
@@ -34,7 +34,7 @@ uuid = { version = "0.8.1", features = ["v4"] }
 
 [dependencies.glean-core]
 path = ".."
-version = "21.2.0"
+version = "21.2.1-alpha.1"
 
 [target.'cfg(target_os = "android")'.dependencies]
 android_logger = { version = "0.8.5", default-features = false }
diff --git a/gradle-plugin/src/main/groovy/mozilla/telemetry/glean-gradle-plugin/GleanGradlePlugin.groovy b/gradle-plugin/src/main/groovy/mozilla/telemetry/glean-gradle-plugin/GleanGradlePlugin.groovy
index 469de56b13..0eb0372856 100644
--- a/gradle-plugin/src/main/groovy/mozilla/telemetry/glean-gradle-plugin/GleanGradlePlugin.groovy
+++ b/gradle-plugin/src/main/groovy/mozilla/telemetry/glean-gradle-plugin/GleanGradlePlugin.groovy
@@ -367,7 +367,7 @@ subprocess.check_call([
     }
 
     void apply(Project project) {
-        project.ext.glean_version = "21.2.0"
+        project.ext.glean_version = "21.2.1-TESTING1"
 
         File condaDir = setupPythonEnvironmentTasks(project)
         project.ext.set("gleanCondaDir", condaDir)