HP 1650B Programming Reference Manual page 5

Printing History
New editions are complete revisions of the manuai. Update packages,
which are issued between editions, contain additional and replacement
pages to be merged into the manual by the customer. The dates on the
title page change only when a new edition or a new update is published.
No information is incorporated into a reprinting unless it appears as a
prior update; the edition does not change when an update is incorporated.
A software code may be printed before the date; this indicates the version
level of the software product at the time of the manual or update was
issued. Many product updates and fLves do not require manual changes
and, conversely, manual corrections may be done without accompanying
product changes. Therefore, do not expect a one-to-one correspondence
between product updates and manual updates.
Edition 1 August 1989