diff --git a/recipes/README.recipes.md b/recipes/README.recipes.md
index d3dbbc5b3..306934ee2 100644
--- a/recipes/README.recipes.md
+++ b/recipes/README.recipes.md
@@ -14,7 +14,7 @@
   * [gsutil](#recipe_modules-gsutil) (Python3 ✅)
   * [osx_sdk](#recipe_modules-osx_sdk) (Python3 ✅) — The `osx_sdk` module provides safe functions to access a semi-hermetic XCode installation.
   * [presubmit](#recipe_modules-presubmit) (Python3 ✅)
-  * [tryserver](#recipe_modules-tryserver)
+  * [tryserver](#recipe_modules-tryserver) (Python3 ✅)
   * [windows_sdk](#recipe_modules-windows_sdk) (Python3 ✅) — The `windows_sdk` module provides safe functions to access a hermetic Microsoft Visual Studio installation.
 
 **[Recipes](#Recipes)**
@@ -39,10 +39,10 @@
   * [presubmit:examples/full](#recipes-presubmit_examples_full) (Python3 ✅)
   * [presubmit:tests/execute](#recipes-presubmit_tests_execute) (Python3 ✅)
   * [presubmit:tests/prepare](#recipes-presubmit_tests_prepare) (Python3 ✅)
-  * [tryserver:examples/full](#recipes-tryserver_examples_full)
-  * [tryserver:tests/gerrit_change_fetch_ref_timeout](#recipes-tryserver_tests_gerrit_change_fetch_ref_timeout)
-  * [tryserver:tests/gerrit_change_owner](#recipes-tryserver_tests_gerrit_change_owner)
-  * [tryserver:tests/gerrit_change_target_ref](#recipes-tryserver_tests_gerrit_change_target_ref)
+  * [tryserver:examples/full](#recipes-tryserver_examples_full) (Python3 ✅)
+  * [tryserver:tests/gerrit_change_fetch_ref_timeout](#recipes-tryserver_tests_gerrit_change_fetch_ref_timeout) (Python3 ✅)
+  * [tryserver:tests/gerrit_change_owner](#recipes-tryserver_tests_gerrit_change_owner) (Python3 ✅)
+  * [tryserver:tests/gerrit_change_target_ref](#recipes-tryserver_tests_gerrit_change_target_ref) (Python3 ✅)
   * [windows_sdk:examples/full](#recipes-windows_sdk_examples_full) (Python3 ✅)
 ## Recipe Modules
 
@@ -863,9 +863,9 @@ Returns:
 &emsp; **@property**<br>&mdash; **def [presubmit\_support\_path](/recipes/recipe_modules/presubmit/api.py#24)(self):**
 ### *recipe_modules* / [tryserver](/recipes/recipe_modules/tryserver)
 
-[DEPS](/recipes/recipe_modules/tryserver/__init__.py#5): [gerrit](#recipe_modules-gerrit), [git](#recipe_modules-git), [git\_cl](#recipe_modules-git_cl), [recipe\_engine/buildbucket][recipe_engine/recipe_modules/buildbucket], [recipe\_engine/context][recipe_engine/recipe_modules/context], [recipe\_engine/json][recipe_engine/recipe_modules/json], [recipe\_engine/path][recipe_engine/recipe_modules/path], [recipe\_engine/platform][recipe_engine/recipe_modules/platform], [recipe\_engine/properties][recipe_engine/recipe_modules/properties], [recipe\_engine/python][recipe_engine/recipe_modules/python], [recipe\_engine/raw\_io][recipe_engine/recipe_modules/raw_io], [recipe\_engine/step][recipe_engine/recipe_modules/step]
+[DEPS](/recipes/recipe_modules/tryserver/__init__.py#7): [gerrit](#recipe_modules-gerrit), [git](#recipe_modules-git), [git\_cl](#recipe_modules-git_cl), [recipe\_engine/buildbucket][recipe_engine/recipe_modules/buildbucket], [recipe\_engine/context][recipe_engine/recipe_modules/context], [recipe\_engine/json][recipe_engine/recipe_modules/json], [recipe\_engine/path][recipe_engine/recipe_modules/path], [recipe\_engine/platform][recipe_engine/recipe_modules/platform], [recipe\_engine/properties][recipe_engine/recipe_modules/properties], [recipe\_engine/python][recipe_engine/recipe_modules/python], [recipe\_engine/raw\_io][recipe_engine/recipe_modules/raw_io], [recipe\_engine/step][recipe_engine/recipe_modules/step]
 
-PYTHON_VERSION_COMPATIBILITY: PY2
+PYTHON_VERSION_COMPATIBILITY: PY2+3
 
 #### **class [TryserverApi](/recipes/recipe_modules/tryserver/api.py#27)([RecipeApi][recipe_engine/wkt/RecipeApi]):**
 
@@ -1206,32 +1206,32 @@ PYTHON_VERSION_COMPATIBILITY: PY2+3
 &mdash; **def [RunSteps](/recipes/recipe_modules/presubmit/tests/prepare.py#28)(api, patch_project, patch_repository_url):**
 ### *recipes* / [tryserver:examples/full](/recipes/recipe_modules/tryserver/examples/full.py)
 
-[DEPS](/recipes/recipe_modules/tryserver/examples/full.py#5): [gerrit](#recipe_modules-gerrit), [tryserver](#recipe_modules-tryserver), [recipe\_engine/buildbucket][recipe_engine/recipe_modules/buildbucket], [recipe\_engine/json][recipe_engine/recipe_modules/json], [recipe\_engine/path][recipe_engine/recipe_modules/path], [recipe\_engine/platform][recipe_engine/recipe_modules/platform], [recipe\_engine/properties][recipe_engine/recipe_modules/properties], [recipe\_engine/python][recipe_engine/recipe_modules/python], [recipe\_engine/raw\_io][recipe_engine/recipe_modules/raw_io], [recipe\_engine/step][recipe_engine/recipe_modules/step]
+[DEPS](/recipes/recipe_modules/tryserver/examples/full.py#7): [gerrit](#recipe_modules-gerrit), [tryserver](#recipe_modules-tryserver), [recipe\_engine/buildbucket][recipe_engine/recipe_modules/buildbucket], [recipe\_engine/json][recipe_engine/recipe_modules/json], [recipe\_engine/path][recipe_engine/recipe_modules/path], [recipe\_engine/platform][recipe_engine/recipe_modules/platform], [recipe\_engine/properties][recipe_engine/recipe_modules/properties], [recipe\_engine/python][recipe_engine/recipe_modules/python], [recipe\_engine/raw\_io][recipe_engine/recipe_modules/raw_io], [recipe\_engine/step][recipe_engine/recipe_modules/step]
 
-PYTHON_VERSION_COMPATIBILITY: PY2
+PYTHON_VERSION_COMPATIBILITY: PY2+3
 
-&mdash; **def [RunSteps](/recipes/recipe_modules/tryserver/examples/full.py#21)(api):**
+&mdash; **def [RunSteps](/recipes/recipe_modules/tryserver/examples/full.py#23)(api):**
 ### *recipes* / [tryserver:tests/gerrit\_change\_fetch\_ref\_timeout](/recipes/recipe_modules/tryserver/tests/gerrit_change_fetch_ref_timeout.py)
 
-[DEPS](/recipes/recipe_modules/tryserver/tests/gerrit_change_fetch_ref_timeout.py#7): [gerrit](#recipe_modules-gerrit), [tryserver](#recipe_modules-tryserver), [recipe\_engine/buildbucket][recipe_engine/recipe_modules/buildbucket], [recipe\_engine/properties][recipe_engine/recipe_modules/properties]
+[DEPS](/recipes/recipe_modules/tryserver/tests/gerrit_change_fetch_ref_timeout.py#9): [gerrit](#recipe_modules-gerrit), [tryserver](#recipe_modules-tryserver), [recipe\_engine/buildbucket][recipe_engine/recipe_modules/buildbucket], [recipe\_engine/properties][recipe_engine/recipe_modules/properties]
 
-PYTHON_VERSION_COMPATIBILITY: PY2
+PYTHON_VERSION_COMPATIBILITY: PY2+3
 
-&mdash; **def [RunSteps](/recipes/recipe_modules/tryserver/tests/gerrit_change_fetch_ref_timeout.py#15)(api):**
+&mdash; **def [RunSteps](/recipes/recipe_modules/tryserver/tests/gerrit_change_fetch_ref_timeout.py#17)(api):**
 ### *recipes* / [tryserver:tests/gerrit\_change\_owner](/recipes/recipe_modules/tryserver/tests/gerrit_change_owner.py)
 
-[DEPS](/recipes/recipe_modules/tryserver/tests/gerrit_change_owner.py#7): [gerrit](#recipe_modules-gerrit), [tryserver](#recipe_modules-tryserver), [recipe\_engine/buildbucket][recipe_engine/recipe_modules/buildbucket]
+[DEPS](/recipes/recipe_modules/tryserver/tests/gerrit_change_owner.py#9): [gerrit](#recipe_modules-gerrit), [tryserver](#recipe_modules-tryserver), [recipe\_engine/buildbucket][recipe_engine/recipe_modules/buildbucket]
 
-PYTHON_VERSION_COMPATIBILITY: PY2
+PYTHON_VERSION_COMPATIBILITY: PY2+3
 
-&mdash; **def [RunSteps](/recipes/recipe_modules/tryserver/tests/gerrit_change_owner.py#14)(api):**
+&mdash; **def [RunSteps](/recipes/recipe_modules/tryserver/tests/gerrit_change_owner.py#16)(api):**
 ### *recipes* / [tryserver:tests/gerrit\_change\_target\_ref](/recipes/recipe_modules/tryserver/tests/gerrit_change_target_ref.py)
 
-[DEPS](/recipes/recipe_modules/tryserver/tests/gerrit_change_target_ref.py#7): [gerrit](#recipe_modules-gerrit), [tryserver](#recipe_modules-tryserver), [recipe\_engine/buildbucket][recipe_engine/recipe_modules/buildbucket], [recipe\_engine/properties][recipe_engine/recipe_modules/properties], [recipe\_engine/step][recipe_engine/recipe_modules/step]
+[DEPS](/recipes/recipe_modules/tryserver/tests/gerrit_change_target_ref.py#9): [gerrit](#recipe_modules-gerrit), [tryserver](#recipe_modules-tryserver), [recipe\_engine/buildbucket][recipe_engine/recipe_modules/buildbucket], [recipe\_engine/properties][recipe_engine/recipe_modules/properties], [recipe\_engine/step][recipe_engine/recipe_modules/step]
 
-PYTHON_VERSION_COMPATIBILITY: PY2
+PYTHON_VERSION_COMPATIBILITY: PY2+3
 
-&mdash; **def [RunSteps](/recipes/recipe_modules/tryserver/tests/gerrit_change_target_ref.py#16)(api):**
+&mdash; **def [RunSteps](/recipes/recipe_modules/tryserver/tests/gerrit_change_target_ref.py#18)(api):**
 ### *recipes* / [windows\_sdk:examples/full](/recipes/recipe_modules/windows_sdk/examples/full.py)
 
 [DEPS](/recipes/recipe_modules/windows_sdk/examples/full.py#7): [windows\_sdk](#recipe_modules-windows_sdk), [recipe\_engine/platform][recipe_engine/recipe_modules/platform], [recipe\_engine/properties][recipe_engine/recipe_modules/properties], [recipe\_engine/step][recipe_engine/recipe_modules/step]
diff --git a/recipes/recipe_modules/tryserver/__init__.py b/recipes/recipe_modules/tryserver/__init__.py
index d40c8f490..2485bf038 100644
--- a/recipes/recipe_modules/tryserver/__init__.py
+++ b/recipes/recipe_modules/tryserver/__init__.py
@@ -2,6 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+PYTHON_VERSION_COMPATIBILITY = 'PY2+3'
+
 DEPS = [
   'gerrit',
   'git',
diff --git a/recipes/recipe_modules/tryserver/examples/full.py b/recipes/recipe_modules/tryserver/examples/full.py
index 1fe92e83b..49b6eaad9 100644
--- a/recipes/recipe_modules/tryserver/examples/full.py
+++ b/recipes/recipe_modules/tryserver/examples/full.py
@@ -2,6 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+PYTHON_VERSION_COMPATIBILITY = 'PY2+3'
+
 DEPS = [
   'gerrit',
   'recipe_engine/buildbucket',
diff --git a/recipes/recipe_modules/tryserver/tests/gerrit_change_fetch_ref_timeout.py b/recipes/recipe_modules/tryserver/tests/gerrit_change_fetch_ref_timeout.py
index cf39ba06c..c495fec0f 100644
--- a/recipes/recipe_modules/tryserver/tests/gerrit_change_fetch_ref_timeout.py
+++ b/recipes/recipe_modules/tryserver/tests/gerrit_change_fetch_ref_timeout.py
@@ -4,6 +4,8 @@
 
 from recipe_engine import post_process
 
+PYTHON_VERSION_COMPATIBILITY = 'PY2+3'
+
 DEPS = [
     'gerrit',
     'recipe_engine/buildbucket',
diff --git a/recipes/recipe_modules/tryserver/tests/gerrit_change_owner.py b/recipes/recipe_modules/tryserver/tests/gerrit_change_owner.py
index 5bbd7c5b3..990cf8866 100644
--- a/recipes/recipe_modules/tryserver/tests/gerrit_change_owner.py
+++ b/recipes/recipe_modules/tryserver/tests/gerrit_change_owner.py
@@ -4,6 +4,8 @@
 
 from recipe_engine import post_process
 
+PYTHON_VERSION_COMPATIBILITY = 'PY2+3'
+
 DEPS = [
     'recipe_engine/buildbucket',
     'gerrit',
diff --git a/recipes/recipe_modules/tryserver/tests/gerrit_change_target_ref.py b/recipes/recipe_modules/tryserver/tests/gerrit_change_target_ref.py
index 4878e200e..fd84d09cc 100644
--- a/recipes/recipe_modules/tryserver/tests/gerrit_change_target_ref.py
+++ b/recipes/recipe_modules/tryserver/tests/gerrit_change_target_ref.py
@@ -4,6 +4,8 @@
 
 from recipe_engine import post_process
 
+PYTHON_VERSION_COMPATIBILITY = 'PY2+3'
+
 DEPS = [
     'gerrit',
     'recipe_engine/buildbucket',