most 3.13 saves load fine in 3.17. MP games are often password protected though - which also protects the assets - in that case you'd need to remove the admin password in 3.13 - then patch and reset an admin password in 3.17 and you *should* be fine.
the most secure way to go though would be either to
- remain in 3.13 for the duration
or
- use a dual install
make a copy of the bts folder so that you have two looking like this:
...\program files\firaxis games\sid meier's civilization 4\beyond the sword\
and
...\program files\firaxis games\sid meier's civilization 4\beyond the sword copy\
if you patch then only
...\program files\firaxis games\sid meier's civilization 4\beyond the sword\
will be patched (and all shortcuts will point to it) - but you can manually start the game by using the .exe in
...\program files\firaxis games\sid meier's civilization 4\beyond the sword copy\
for a 3.13 game - you can even create a shortcut to 3.13...
the most secure way to go though would be either to
- remain in 3.13 for the duration
or
- use a dual install
Spoiler dual install :
make a copy of the bts folder so that you have two looking like this:
...\program files\firaxis games\sid meier's civilization 4\beyond the sword\
and
...\program files\firaxis games\sid meier's civilization 4\beyond the sword copy\
if you patch then only
...\program files\firaxis games\sid meier's civilization 4\beyond the sword\
will be patched (and all shortcuts will point to it) - but you can manually start the game by using the .exe in
...\program files\firaxis games\sid meier's civilization 4\beyond the sword copy\
for a 3.13 game - you can even create a shortcut to 3.13...