Reverting changes done by release script due to failed
vote for 0.20.0 RC0

Revert "Preparing RELEASE-NOTES.md for release."

This reverts commit a60367626e71786fa7a23a49510a437986a9a074.

Revert "Updating CHANGELOG for 0.20.0 release."

This reverts commit 5a26413f72b8a428f286bed286aa4612c4123884.

Revert "Incrementing snapshot version to 0.21.0-SNAPSHOT."

This reverts commit a12b84444e0ba4227e6a41b0f7e82045b2dcc016.
diff --git a/.auroraversion b/.auroraversion
index 6a8fc0b..8bec379 100644
--- a/.auroraversion
+++ b/.auroraversion
@@ -1 +1 @@
-0.21.0-SNAPSHOT
+0.20.0-SNAPSHOT
diff --git a/CHANGELOG b/CHANGELOG
index 5ac2f01..40b0096 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,24 +1,3 @@
-Aurora 0.20.0
---------------------------------------------------------------------------------
-## Bug
-    * [AURORA-1963] - Structdump endpoint shows thrift metadata
-    * [AURORA-1965] - LaunchException needs transient task timeout for reschedule
-    * [AURORA-1956] - test_du_diskcollector fails on macOS
-    * [AURORA-1233] - primary_port warning does not appear to respect portmap
-    * [AURORA-1959] - Missing Ops prevent upgrade from 0.19 to master
-
-## Story
-    * [AURORA-1380] - Upgrade to guice 4.0
-    * [AURORA-1249] - Upgrade 3rdparty python dependencies
-    * [AURORA-1412] - Conflicting `slow_query_log_threshold` arguments for aurora-scheduler
-    * [AURORA-1471] - Reconsider use of shiro-guice
-
-## Task
-    * [AURORA-1964] - Move Vagrant setup from Trusty to Xenial
-    * [AURORA-1901] - Expose thrift workload stats on pruneTasks() invocations
-    * [AURORA-1707] - Remove deprecated resource fields in TaskConfig and ResourceAggregate
-
-
 Aurora 0.19.0
 --------------------------------------------------------------------------------
 ## Bug
diff --git a/RELEASE-NOTES.md b/RELEASE-NOTES.md
index 8e43760..4f850bc 100644
--- a/RELEASE-NOTES.md
+++ b/RELEASE-NOTES.md
@@ -1,18 +1,4 @@
-0.21.0 (unreleased)
-===================
-
-### New/updated:
-- Added `executor_config` field to the Job object of the DSL which will populate
-  `JobConfiguration.TaskConfig.ExecutorConfig`. This allows for using custom executors defined
-  through the `--custom_executor_config` scheduler flag. See our
-  [custom-executors](docs/features/custom-executors.md) documentation for more information.
-- Added support in Thermos Observer for delegating disk usage monitoring to Mesos agent. The feature
-  can be enabled via `--enable_mesos_disk_collector` flag, in which case Observer will use the
-  agent's containers HTTP API to query the amount of used bytes for each container. Note that disk
-  isolation should be enabled in Mesos agent. This feature is not compatible with authentication
-  enabled agents.
-
-0.20.0
+0.20.0 (unreleased)
 ===================
 
 ### New/updated:
@@ -29,6 +15,15 @@
 - Added the ability to inject custom offer holding and scheduling logic via the `-offer_set_module`
   scheduler flag. To take advantage of this feature, you will need to implement the `OfferSet`
   interface.
+- Added `executor_config` field to the Job object of the DSL which will populate
+  `JobConfiguration.TaskConfig.ExecutorConfig`. This allows for using custom executors defined
+  through the `--custom_executor_config` scheduler flag. See our
+  [custom-executors](docs/features/custom-executors.md) documentation for more information.
+- Added support in Thermos Observer for delegating disk usage monitoring to Mesos agent. The feature
+  can be enabled via `--enable_mesos_disk_collector` flag, in which case Observer will use the
+  agent's containers HTTP API to query the amount of used bytes for each container. Note that disk
+  isolation should be enabled in Mesos agent. This feature is not compatible with authentication
+  enabled agents.
 
 ### Deprecations and removals: