Hi,

Trying to use DBD::Informix.

Oracle Linux Server 8.10
Perl v5.26.3
DBI 1.641-4
DBD::Informix 2018.1031
CSDK 4.50.FC5
Informix Dynamic Server 11.70.FC5XE

When I execute
$dbh_bl->{AutoCommit} = 0;
Perl aborts with the above message,
DBD::Informix - Cannot unset AutoCommit for unlogged databases

All our databases are logged, so I have no clue why the error occurs.

Please show a complete reproduction script - it should be under 10 lines long.  The connection string is very important.
You could send it to my Gmail account - which is where DBD::Informix support is handled these days.
It's slightly odd to be using CSDK 4.50 with IDS 11.70 (it goes with version 14.10 most naturally), but I don't think that's a contributing factor.

The Informix environment would be useful.

So would the result of running "SELECT * FROM sysmaster:sysdatabases"