The bug 33039 :Add ability to specify a template for serial subscription "Published on (text)" field explains that template toolkit can be used for including fields from the subscription within this text box. Unfortunately, as the bug is lined out, the " Keys available are the Koha::Subscription object as 'subscription' and the following serial table columns as keys: serialseq serialseq_x serialseq_y serialseq_z subscriptionid biblionumber status planneddate publisheddate publisheddateext notes routingnotes So your example template could be "[% subscription.subscriptionid %] [% biblionumber %]" The object, 'subscription' does not work in this template. If a library wanted to include the planned date, they would use [% planneddate %] and not use [% subscription.planneddate %]. I also would like to point out bug 35867- https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=35867