I have not had to upgrade the Razor mediator yet. However, with the recent memory leak fixes, in v1.3.3 I will probably be doing this soon.

The upgrade should just be a matter of uninstalling v1.2 and then re-installing v1.3.

The steps that I would probably take are:

1. Take the CMS (CME and Core Service) offline to prevent users from trying to publish (or open templates) during the upgrade.
2. Back up the Tridion CM database (may be being over cautious here)
3. Make a backup of the Tridion.ContentManager.config file (the documentation says that this is done automatically during the uninstall, but you can never be too careful!)
4. Uninstall version 1.2
5. Restart the Tridion Content Manager COM+ Package, the Tridion Publisher service, and Template Builder (if it’s open).
6. Install version 1.3.3 (it contains memory leak fixes over 1.3)
7. Re-instate any imports or configuration changes in to the Tridion.ContentManager.config file that you may need
8. Restart the Tridion Content Manager COM+ Package, the Tridion Publisher service, and Template Builder (if it’s open).
9. Test (including publishing)
10. Make the CMS available again.

Hope this helps!

I have not had to upgrade the Razor mediator yet. However, with the recent memory leak fixes, in v1.3.3 I will probably be doing this soon.

The upgrade should just be a matter of uninstalling v1.2 and then re-installing v1.3.

The steps that I would probably take are:

1. Take the CMS (CME and Core Service) offline to prevent users from trying to publish (or open templates) during the upgrade.
2. Back up the Tridion CM database (may be being over cautious here)
3. Make a backup of the Tridion.ContentManager.config file (the documentation says that this is done automatically during the uninstall, but you can never be too careful!)
4. Uninstall version 1.2
5. Restart the Tridion Content Manager COM+ Package, the Tridion Publisher service, and Template Builder (if it’s open).
6. Install version 1.3.3 (it contains memory leak fixes over 1.3)
7. Re-instate any imports or configuration changes in to the Tridion.ContentManager.config file that you may need
8. Restart the Tridion Content Manager COM+ Package, the Tridion Publisher service, and Template Builder (if it’s open).
9. Test (including publishing)
10. Make the CMS available again.

You will want to do this in development, before moving it up through the DTAP environments.

You may want to consider the amends to the functionality between 1.2 and 1.3.3 in the Razor Mediator Change Log whilst testing.

Hope this helps!