This is a massive upgrade, and a lot of the minor annoyances that users were finding about Lemmy has been fixed. You can check the above links for all the changes implemented but some of the major ones are:
Websockets replaced by HTTP: What this means for you is that instances will feel snappier due to less load, and the annoying sudden flood of new posts when browing hot is also gone. In general hot/active sorting has been reworked and feel much better to browse.
Links that would take you off-instance should now get automatically converted to ones that don’t. And just writing the name should be enough to turn it into a link. So no more manually searching for the linked communities you find in the comments.
Support for 2-Factor Authentification.
Custom emojis for Instances.
Support for PWA.
A Share Button.
Improvements to overall look and feel of Lemmy.
Not to mention many under the hood changes like database optimizations and bug fixes. This is a very big version upgrade that's come at just the right time.
However, some Instance admins encountered errors when trying to upgrade. And captchas, which we rely on to prevent bots from flooding in, will come back only in version 0.18.1.
So our options are to either upgrade now, maybe have some downtime and to turn on registration applications, or wait until v0.18.1 is released before upgrading (which shouldn't take more than a few days).
We are leaning towards option 2 for now, but interested in hearing what others have to say.
I updated my small instance, it worked great. Until I rebooted the server then it stopped working entirely. I tried restarting the database and the app separately, but it never came back up. I had to wipe and reinstall as downgrading didn't work either. Due to issues with names no longer federating if the instance is recreated with the same domain and name I had to change my subdomain entirely as well. If for example a user was named user1@instance1.tld and you reinstall that instance using instance1.tld. If you recreate the user user1@instance1.tld, it will not federate any comments.
I may be a small use case, but it has made sure I'll be waiting a good long time before upgrading again.