[exim] Question for old-timers: mailbox sorting

I have been asked for evidence of when local part suffixes were first
used for sorting messages into different folders (for a patent issue).
The suffixes were in Exim from the start (and were previously in Smail
3), but the earliest clue I have about using them for sorting is in the
Exim 1.62 documentation. This is too late (1997). Unfortunately, I do
not have any earlier Exim sources or documentation apart from a 0.12
source which has incomplete documentation (and pre-dates filters, which
were added at 0.43).

Do any old-timers on this list have any Exim sources or documentation
from release 0.54 or earlier? Or evidence of the use of local part
suffixes for message sorting from 1996 or earlier? If so, please get in
touch.

Philip

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Philip Hazel, University of Cambridge Computing Service.