Upgrading from 6.22/09 to 6.24/02

[Wile_E_Coyote]

You can have MULTIPLE (different) ROOT versions installed SIMULTANEOUSLY in different directories (and easily switch between them). See e.g.:

Sourcing root for all users

That’s more or less what I say, too. Just do NOT put any “default ROOT” settings in any standard “environment” files. Every user should always be expected to source an appropriate “thisroot.[c]sh” for the ROOT version that [s]he wants to use. Note: you can easily create shell aliases for them (and put them in any standard “environment” files) … something like: alias root-53436='source /opt/ROOT/releases/root_v5.34.36/bin/thisroot.sh' alias root-60902='source /opt/ROOT/releases/root_v6.09.02/…