Database failure after update to 2.7

Updated the plugin to 2.7 yesterday, after which the database suffered a problem: all previous newsletters had gone, the mailinglist showed no subscribers.

The settings pages showed lots of WordPress database error messages, all based on the fact that [Table ‘[username].wordpr_wysija_user’ doesn’t exist]. Did not do anything beforehand that could have removed said table.

Reverted back to 2.6.19 manually, but that didn’t help. Your help would be appreciated. Thank you!

https://ww.wp.xz.cn/plugins/wysija-newsletters/