It would be useful for Koha to have a 'Deprecated' function, which would send a warning about the caller() function and the version of Koha where the function will be deprecated, and what it will be replaced by... so let's say that C4::Adequate::DoEET() is being replaced by Koha::Awesome->sauce(). in Koha 18.11. In versions of koha prior to 18.11, we add a call to deprecated( "18.11", "Koha::Awesome->sauce()"); at the beginning of C4::Adequate::DoEET(). Then, when C4::Adequate::DoEET() is called, this would generate the following message in the logs: "C4::Adequate::DoEET is deprecated and will be removed in Koha 18.11. It will be replaced by Koha::Awesome->sauce()." This would allow plugin authors to know that they will need to patch their plugins before they break on upgrade. This is a bare-bones implementation of deprecated(): sub deprecated { my ( $version, $replacement ) = @_; my ( $package, $filename, $line, $subroutine, $hasargs, $wantarray, $evaltext, $is_require, $hints, $bitmask, $hinthash ) = caller(1); warn( "${subroutine} is deprecated and will be removed" . " in Koha version $version." . defined( $replacement ) ? " It will be replaced by ${replacement}." : "" ); }