The upgrade from version 2.20 to 2.60 is free - as are all 2.x upgrades.

2.60 will run fine without uninstalling 2.20 first, but one extra DLL will be left in place (that was obsoleted in the 2.30 release). It won't hurt anything to just install on top of it - it will just use an extra 100K of disk space until you uninstall.

- Pete