I recently upgraded our web server to PHP 7.2.  We had been using a third party repository for PHP 7.1 but with Bionic Beaver (the latest Ubuntu) there were too many conflicts that broke it.  As a result I removed the third party repository and upgraded to PHP 7.2.

     Two things were badly broken by 7.2, OwnCloud and Squirrelmail.  I upgraded Squirrelmail to the most recent and it is mostly fixed, still bitches sometimes when mail with certain HTML is present.

     OwnCloud does not plan on being PHP 7.2 compatible until version 11.  There is a real dearth of applications for it, where NextCloud has just exploded with new applications and does work properly with PHP 7.2.  This being the case I am going to discontinue support for OwnCloud at least until they get 7.2 clean.