I'm just having a squiz at the release notes.
Things that are interesting:
Moving away from websockets: Honestly, yes, good plan. The live updates, while impressive, just aren't needed, and the additional load it must put on things is a bit silly when scaling up. This should mean making bots is a lot easier, and efficient. API docs here: https://join-lemmy.org/api/
I'm hoping that in the jumble, this also fixes the refresh/infinity loading issues we've seen. ( This commit which went into 18.0 seems to be the fix!)
2FA: Also a great move. TOTP is a nice second step, if anyone would like a run-down of options you can use, give me a shout once it's online.
Custom emojis: That's going to be fun. Might need a bit of self control to avoid over 9000 emojis clogging up threads.
Captchas are not available (possibly related to the demise of websockets?), and will not be back until 18.1.
After the spam tsunami the other day, that alone might be enough reason to hold off upgrading until 18.1 releases.
Preview button now changes to "Edit" when you've entered Preview mode (kinda nice, better UX than it just being a toggle)
Ban has been changed to Ban From Community to be more clear what it achieves.
The main reason I see for not holding off is a bug I encountered on day one of moving to lemmy. Moderators from a different instance to the community "home instance" changing the settings (description, etc.) just breaks the community, kills its federation and causes the link to 404, the only way to resolve is a sysadmin changing the value in their database. That's gnarly and is well worth updating for. Hopefully in future the lemmy devs will do low risk patch releases for critical bugs, alongside feature releases, so that you can update for stability without signing up for new features with new bugs.
Apart from the silly voice, what happened to maybe waiting a couple hours/days/months before upgrading? Who knows what new bugs this new version introduces.
I think there have been a few teething troubles gör those rolling out the update as soon as it dropped. Might as well let someone else take that bullet.