diff --git a/Dockerfile b/Dockerfile
index 79c125b..f7ba51d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
-FROM tootsuite/mastodon-streaming:v4.4 as streaming
+FROM tootsuite/mastodon-streaming:v4.5.7 as streaming
 
-FROM tootsuite/mastodon:v4.4
+FROM tootsuite/mastodon:v4.5.7
 
 USER root
 
diff --git a/Dockerfile.redis b/Dockerfile.redis
index 8dcd469..5209fcf 100644
--- a/Dockerfile.redis
+++ b/Dockerfile.redis
@@ -1,4 +1,4 @@
-FROM redis:alpine
+FROM redis:7-alpine
 ADD start-redis-server.sh /usr/bin/
 RUN chmod +x /usr/bin/start-redis-server.sh
 CMD ["start-redis-server.sh"]
diff --git a/README.md b/README.md
index 6c5b2dd..baeaf85 100644
--- a/README.md
+++ b/README.md
@@ -21,10 +21,10 @@ fly apps create mastodon-example
 ### Secrets
 
 ```bash
-export SECRET_KEY_BASE=$(docker run --rm -it tootsuite/mastodon:latest bin/rake secret)
-export OTP_SECRET=$(docker run --rm -it tootsuite/mastodon:latest bin/rake secret)
-fly secrets set OTP_SECRET=$OTP_SECRET SECRET_KEY_BASE=$SECRET_KEY_BASE
-docker run --rm -e OTP_SECRET=$OTP_SECRET -e SECRET_KEY_BASE=$SECRET_KEY_BASE -it tootsuite/mastodon:latest bin/rake mastodon:webpush:generate_vapid_key | sed 's/\r//' | fly secrets import
+export MASTODON_VERSION=v4.5.7
+export SECRET_KEY_BASE=$(docker run --rm -it tootsuite/mastodon:$MASTODON_VERSION bin/rake secret)
+fly secrets set SECRET_KEY_BASE=$SECRET_KEY_BASE
+docker run --rm -e SECRET_KEY_BASE=$SECRET_KEY_BASE -it tootsuite/mastodon:$MASTODON_VERSION bin/rake mastodon:webpush:generate_vapid_key | sed 's/\r//' | fly secrets import
 ```
 
 ### Redis server
@@ -134,15 +134,17 @@ If your instance is getting slow or falling over, you may find [Scaling Mastodon
 
 ### Upgrading Mastodon
 
-To upgrade to a new version of Mastodon, change the version number on the first line of `Dockerfile`, and then check the [release notes](https://github.com/mastodon/mastodon/blob/main/CHANGELOG.md) for upgrade instructions.
+To upgrade to a new version of Mastodon, update the Mastodon image tags in [`Dockerfile`](./Dockerfile), and then check the [release notes](https://github.com/mastodon/mastodon/blob/main/CHANGELOG.md) for upgrade instructions.
 
-If there are migrations that need to be run, make sure that the release command in [`fly.toml`](./fly.toml) is uncommented.
+This repo keeps the Fly release command enabled in [`fly.toml`](./fly.toml), so standard post-deploy migrations run automatically during `fly deploy`.
+
+Before upgrading to Mastodon 4.5.x or newer, make sure your Fly Postgres app is already on PostgreSQL 14 or newer and your Redis app is already on Redis 7 or newer.
 
 If there are migrations that must be run before deploying to avoid downtime, you can run the pre-deploy migrations using a second app. By scaling this app to a VM count of zero, it won't add to our bill, but it will let us run the pre-deploy migrations as a release command before the web processes get the new code.
 
 ```bash
 fly apps create mastodon-example-predeploy
-bin/fly-predeploy secrets set OTP_SECRET=placeholder SECRET_KEY_BASE=placeholder
+bin/fly-predeploy secrets set SECRET_KEY_BASE=placeholder
 bin/fly-predeploy secrets set $(fly ssh console -C env | grep DATABASE_URL)
 bin/fly-predeploy scale memory 1024
 bin/fly-predeploy scale count 0
diff --git a/fly.toml b/fly.toml
index 3c9aa28..f356f24 100644
--- a/fly.toml
+++ b/fly.toml
@@ -8,9 +8,10 @@ swap_size_mb = 1024
 [[vm]]
   memory = "1024"
 
-## Uncomment if you are upgrading Mastodon. See README.md for details.
-# [deploy]
-#   release_command = "bin/rails db:migrate"
+## Keep standard post-deploy migrations enabled.
+## Use fly.predeploy.toml for releases that require pre-deployment migrations.
+[deploy]
+  release_command = "bin/rails db:migrate"
 
 [env]
   LOCAL_DOMAIN = "social.python.it"
@@ -52,7 +53,7 @@ swap_size_mb = 1024
 #   rails = "./overmind start -x rails"
 #   # If you need to run more sidekiq workers, scale up this group
 #   # by running `fly scale count N --group sidekiq`
-#   sidekiq = "bash -c 'bundle exec sidekiq -c $MAX_THREADS -q default,8 -q push,6 -q ingress,4 -q mailers,2 -q pull'"
+#   sidekiq = "bash -c 'bundle exec sidekiq -c $MAX_THREADS -q default,8 -q push,6 -q ingress,4 -q mailers,2 -q pull,1 -q fasp,1'"
 #   # The schedule queue can only ever have one worker process at a time
 #   # by running fly scale count 1 --group schedule
 #   schedule = "bash -c 'bundle exec sidekiq -c $MAX_THREADS'"