for the most part, yes. However, if any code lines has changed their syntax~format between versions, then you'll have to update~convert your old code lines to the new format~syntax required of them. The main change was with the list+dictionary Attributes' syntax~format.
http://docs.textadventures.co.uk/quest/upgrade_notes.html
an extremely useful link, for this very reason, hehe :D
P.S.
and you also got to change the very first~top code line in your game file, from:
<asl version="###">
to:
<asl version="###">
for example:
from:
<asl version="550">
to:
<asl version="560">
and lastly, the quest engine only cares about the tens place, so don't do this:
<asl version="551">
~OR~
<asl version="565">
as '<asl version="550">' covers~works_for: v550 to v559
as '<asl version="560">' covers~works_for: v560 to v569
a game file's (*.aslx) creation tag block:
<asl version="###">
// your mass of game code~content
</asl>
a library file's (*.aslx) creation tag block:
<library>
// your mass of code
</libary>