freePBX-16 Superfecta LDAP-lookup error

The LDAP source module in CID Superfecta does not work anymore on freePBX 16 (and above?) distro. I use a TurnKey openLDAP server and it has been working for many years. It still works, when I access openLDAP from a freePBX 15 server.

The error is "A non-numeric value encountered..."

The solution is described here

I changed line 191 in the LDAP-source-file accordingly...from

$thenumber = substr($thenumber, (-1*$run_param[‘Filter_Length’]));

to

$thenumber = substr($thenumber, (-1*(int)$run_param[‘Filter_Length’]));

...now it works again. It seems to be related to php >7.1