This enables timeline for headquarter buildings.
It does not require a new makeobj, however pak-set authors will have to change their dat-files to enter meaningfull intro/retire dates. The default in makeobj is 1900 and 2999, this means there will be no headquarters available before 1900 in pak64 and pak.german with this patch.
Another good improvement :)
I will be using this in pak128.Britain.
Excellent!
Incorporated in 3563.
Pak-sets may need to set intro/retire dates for their headquarters, as the default values are 1900 and 2999, that is without proper intro dates no headquarters can be built before 1900.
Further requirement: to be able to upgrade a headquarter, a headquarter building for the next level has to be available.