I ran into the same issue as @RKD2. For me I don’t think this was an issue with MiaB but rather something that Linode changed/updated.
When I logged into the server to see what was going on I noticed that I had some updates to run so I did that then checked to see if that fixed the error. Since I was still getting the error I restarted nginx and some other services with no effect so I rebooted the node which got php working correctly again. In my experience a reboot is not normally necessary but I have run into situations in the past where rebooting allowed everything to reconnect to moved/updated resourced after an update.
For me this fixed the issue and now all is right with the world.
More details for those who care…
I was getting the following error:
PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php/20151012/apc.so' - /usr/lib/php/20151012/apc.so: undefined symbol: zif_apcu_store in Unknown on line 0
I logged into the node and ran sudo apt-get update && sudo apt list --upgradable to check for updates.
The following were in the list of available updates:
php-apcu
php-apcu-bc
php-common
php-igbinary
php-msgpack
php-xml
php7.2-common
php7.2-xml
To fix it I ran an update and upgrade with: sudo apt-get update && sudo apt-get upgrade and after restarting some services without any effect I rebooted the node.
In the end I believe the update, upgrade, and reboot were all that was needed.