This is a follow-up to the discussion at
http://lists.wfu.edu/pipermail/gretl-devel/2014-August/005253.html
By default, the "append" command now strictly appends data (news series
and/or additional observations). The old behavior included the "updating"
of any observations that were in common between the existing in-memory
dataset and the file specified with "append". This behavior can be called
for by use of the new --update-overlap option.
Allin