To recreate: 1 - Go to Manage Frequencies (/cgi-bin/koha/serials/subscription-frequencies.pl) 2 - create a new frequency, don't enter a value for display order 3 - try to save, get an error: C4::Serials::Frequency::AddSubscriptionFrequency(): DBI Exception: DBD::mysql::st execute failed: Incorrect integer value: '' for column 'displayorder' at row 1 at /kohadevbox/koha/serials/subscription-frequencies.pl line 89 at /usr/share/perl5/DBIx/Class/Exception.pm line 77
Confirmed on master. Same issue for numbering patterns without display order. I have also tested on 20.11 and there it's possible to save the entries with the display order being empty. So something must have changed and the field should not be mandatory or cause such an ugly error.