Does anyone know whether the terms patching and update version mean the same thing? Also is there a resource somewhere I would get notified when there is a patch available? In other words, how could I tell when I need to patch or update my environment?
Q: Does anyone know whether the terms patching and update version mean the same thing?
No, both are different.
What is an Update?
Sitecore releases Updates in timely fashion. These Updates normally have known bug fixes from previous versions and possibly any additional features/functionalities bundled. Every Update comes with Release Notes which have the details about – all fixed bugs, any new features and list of known bugs. Typically every Update have a revision number for ex.
Sitecore Experience Platform 9.0 rev. 171219 (9.0 Update-1). Decoding number 171219 tells that it was released on Dec-19 2017.
What is a Patch?
Sitecore release various patches for specific bugs. This can happen either when you raise a Sitecore Support Ticket or Sitecore releases the patch publicly. A Patch contains fix either for a particular Sitecore version/update or if feasible a specific bug fix for more than 1 Sitecore versions/updates. Typically Patches come with a particular Bug number mentioned in the Release Notes.
Q: Also is there a resource somewhere I would get notified when there is a patch available?
Q: In other words, how could I tell when I need to patch or update my environment?
I would say if you are already on a nearest latest version of Sitecore and struggling with a particular bug which can be resolved by a Patch – Go for it. Else Upgrade to a version which comes with a fix of that bug OOTB. But if you are looking for a new or advanced feature which is not available on your current version, obviously Upgrade is the only option left.
If you implemented a patch earlier and now you have upgraded to a version which come with the fix OOTB, you can rollback the patch by removing the files (Config/Dlls etc) which was included in the patch.
There are two conditions in which I've encountered that relate to updates and patches.
Upgrade with Updates
Upgrade Sitecore versions using the
.update package when moving from Sitecore 8.2u4 to 8.2u6. The update nomenclature may appear as a revision with a date or simply an update number. The use of "update" and "upgrade" may be used interchangeably. Sitecore announces the updates through communication channels such as Sitecore Slack Chat, Twitter, and the Community site.
Patch Sitecore libraries with files provided by Sitecore Support. These are tested specifically with the version of Sitecore you are running and the version of other modules. I had a case where I needed a patch to fix the Switching provider used with the Active Directory module. After upgrading Sitecore, the patch was no longer necessary. You must reach out to Sitecore Support directly for patches.