Nothing gigantic here, but figured I would post it. A couple years ago there were some threads about using a mail client in the nextcloud portal so that you can have calendar, contacts and email in one place. Someone posted a nice “how-to” to set things up with the Rainloop app in Nextcloud (NextCloud RainLoop/Roundcube plugin?).
Now, to me, Rainloop is fine, but it’s no Roundcube, which I am slowly coming to realize is the premier webmail client out there (I have tried so many!). Plus, the Rainloop app really doesn’t have much of any integration with Nextcloud. You can’t pick files, or save contacts or calendars directly into Nextcloud. The only real benefit is that you can set it to autologin. Nextcloud Mail has all the integration features, but (a) it is horrendously slow in my experience; (b) has a pretty poor interface; and © anyway can’t be used in MIAB because you need a higher version of php than Nextcloud 18.04 provides.
But there is a super-easy way to get Roundcube into Nextcloud in much the same way as Rainloop is there. Follow the instructions in the link above to enable Nextcloud admin for one of your MIAB users, add the External Sites app, and then add your roundcube address in as an external site. Then when logging in, choose to stay logged in to avoid having to login again after logging into Nextcloud. And that’s it, you have your lovely roundcube right next to calendar and contacts in Nextcloud, and if you set up file and calendar sync on your desktop you can neatly integrate between them all, not as well as you would do if you used the Nextcloud Mail app, but well enough.