I tend to get rid of old products that are not used BEFORE upgrading.
You're at 6.1 so you're not at such a risk. But some poor schmuck still
at V5R4 may find a serious issue when they try to run the UNINSTALL for
various products after the upgrade. Messages like "conversion required -
no observability" or some such thing.
That's a drastic example, but a good one. Other possibilities are simple
stuff that just works differently. Like some poor fool who uses
CPYFRMSTMF or some such thing to read a stream file to check on a product
In your case I would leave the XE1 and get rid of the others.
And some keep the same name. Like 5761JV1 stays that name with 7.1.
Finally changes to 5770JV1 in 7.2.
Changing to 5770JV1 actually killed one product. They checked licensed
program name - not the java version file.