diff --git a/taskcluster/docker/debian-base/Dockerfile b/taskcluster/docker/debian-base/Dockerfile
index 01e95d4e12a8..c3eebd715cd1 100644
--- a/taskcluster/docker/debian-base/Dockerfile
+++ b/taskcluster/docker/debian-base/Dockerfile
@@ -5,8 +5,8 @@ MAINTAINER Mike Hommey <mhommey@mozilla.com>
 
 ### Add worker user and setup its workspace.
 RUN mkdir /builds && \
-    groupadd -g 500 worker && \
-    useradd -u 500 -g 500 -d /builds/worker -s /bin/bash -m worker && \
+    groupadd -g 1000 worker && \
+    useradd -u 1000 -g 1000 -d /builds/worker -s /bin/bash -m worker && \
     mkdir -p /builds/worker/workspace && \
     chown -R worker:worker /builds
 
diff --git a/taskcluster/docker/google-play-strings/Dockerfile b/taskcluster/docker/google-play-strings/Dockerfile
index 5c1230adbd39..797e9f0b0514 100644
--- a/taskcluster/docker/google-play-strings/Dockerfile
+++ b/taskcluster/docker/google-play-strings/Dockerfile
@@ -2,8 +2,8 @@ FROM          ubuntu:16.04
 MAINTAINER    Johan Lorenzo <jlorenzo+tc@mozilla.com>
 
 RUN mkdir /builds
-RUN groupadd -g 500 worker
-RUN useradd -u 500 -g 500 -d /builds/worker -s /bin/bash -m worker
+RUN groupadd -g 1000 worker
+RUN useradd -u 1000 -g 1000 -d /builds/worker -s /bin/bash -m worker
 
 RUN apt-get update
 RUN apt-get install --yes git python3-setuptools build-essential libssl-dev libffi-dev python3-dev
diff --git a/taskcluster/docker/recipes/run-task b/taskcluster/docker/recipes/run-task
index 029209da34f4..d11e02465fae 100755
--- a/taskcluster/docker/recipes/run-task
+++ b/taskcluster/docker/recipes/run-task
@@ -289,6 +289,13 @@ def main(args):
                   args.group)
             return 1
 
+        if user.pw_name == 'worker' and user.pw_uid != 1000:
+            print('user `worker` must have uid=1000.')
+            return 1
+        if group.gr_name == 'worker' and group.gr_gid != 1000:
+            print('group `worker` must have gid=1000.')
+            return 1
+
         # Find all groups to which this user is a member.
         gids = [g.gr_gid for g in grp.getgrall() if args.group in g.gr_mem]
 
diff --git a/taskcluster/docker/update-verify/Dockerfile b/taskcluster/docker/update-verify/Dockerfile
index 31d593568523..f1b79c3b17c3 100644
--- a/taskcluster/docker/update-verify/Dockerfile
+++ b/taskcluster/docker/update-verify/Dockerfile
@@ -10,8 +10,8 @@ RUN dpkg --add-architecture i386 && apt-get -q update \
     && apt-get clean
 
 RUN mkdir /builds
-RUN groupadd -g 500 worker
-RUN useradd -u 500 -g 500 -d /builds/worker -s /bin/bash -m worker
+RUN groupadd -g 1000 worker
+RUN useradd -u 1000 -g 1000 -d /builds/worker -s /bin/bash -m worker
 WORKDIR /builds/worker
 
 VOLUME /builds/worker/.cache
diff --git a/taskcluster/taskgraph/transforms/task.py b/taskcluster/taskgraph/transforms/task.py
index 651515cfbdf8..0db3638588bb 100644
--- a/taskcluster/taskgraph/transforms/task.py
+++ b/taskcluster/taskgraph/transforms/task.py
@@ -875,7 +875,7 @@ def build_docker_worker_payload(config, task, task_def):
         # string literal in the variable below can be changed. This is
         # preferred to changing run-task because it doesn't require images
         # to be rebuilt.
-        cache_version = 'v2'
+        cache_version = 'v3'
 
         if run_task:
             suffix = '-%s-%s' % (cache_version, _run_task_suffix())