groff's -mm macros have Moved the Footer in version 1.18.
Binary package hint: groff
The footer printed with the -mm macros has changed position between
groff versions 1.17.2 and 1.18 present in Ubuntu 5.04. This is a pain
as turning troff documents written before 5.04 into PostScript no longer
produces the same results despite the document source not changing.
Ubuntu actually provides version 18.104.22.168-7, but it's present in that
too and, as of the time of writing, groff CVS.
Here's a document that shows the problem.
.\" groff -mm -ma4 footermoves.tr >footermoves.ps
.PGFORM 21c-2i 29.7c-1i 1i 1
Footer not in a constant place across groff versions.
If the `.S +1' is commented out the problem doesn't occur.
The non-postprocessed output can be obtained by using -Z: groff -Z -mm
Here's the differences between the two outputs.
@@ -42,10 +42,10 @@
+V748889 [Vertical position different here before printing `fl'.]
@@ -53,7 +53,7 @@