**NOTE:** If you are not installing Sentry from scratch, our recommendation is to visit [On-Premise Stable for Sentry 9.1.2](https://github.com/getsentry/onpremise/tree/stable) as this version may not be fully backward compatible. If you still want to try it out make sure you are on 9.1.2 first, back up your old Docker volumes just in case, and remember that if you haven't set up Redis persistency yourself some of your data (like your stats) may be lost during the upgrade.
There may need to be modifications to the included example config files (`sentry/config.example.yml` and `sentry/sentry.conf.example.py`) to accommodate your needs or your environment (such as adding GitHub credentials). If you want to perform these, do them before you run the install script and copy them without the `.example` extensions in the name (such as `sentry/sentry.conf.py`) before running the `install.sh` script.
Sentry comes with a cleanup cron job that prunes events older than `90 days` by default. If you want to change that, you can change the `SENTRY_EVENT_RETENTION_DAYS` environment variable in `.env` or simply override it in your environment. If you do not want the cleanup cron, you can remove the `sentry-cleanup` service from the `docker-compose.yml`file.
The included `install.sh` script is meant to be idempotent and to bring you to the latest version. What this means is you can and should run `install.sh` to upgrade to the latest version available.
