Are you sure that the warnings appeared when the program was updated (more than a month ago)?
Since when (number of days , hours)do you have these alerts ? Do not say "since the last update"
So far, with avast, this type of detection (false positives or not) has never occurred following an update of the program but always following a VPS update regardless of the program version used.
A backup to the old version will not change this, the VPS version being the same for both versions.
However, you can send both alerts to avast.
https://www.avast.com/false-positive-file-form.phpIf these are proven false positives, the next VPS version will fix this.