This May be a Dumb Question

[Uhura!]

What's the feasibility of converting a 1.1.11 forum to 2.0?

[hadesflames]

For now, SMF 1.1 is still the stable release. Although more and more users are switching over to SMF 2.0 because of the new features, and it being "stable enough"

Changes in SMF 2.0

Edit:

also, look around the developer's blog for more info on changes made in 2.0

[Kays]

Something to remember is that all current installed mods and themes will no longer be compatible.

Although a number of mods are now incorporated into 2.0.

[Nick Whetstone]

As Kays said, most mods and themes will not work. I'd recommend uninstalling them prior to the upgrade to avoid possible errors.