I must have missed this improvement in the change log. I just ran across this as a unit upgrade option while playing LH. This has been on my number one want list since EWOM. Now my highly experienced units don't loose their importance as I research larger group sizes. More game immersion as I get attached to long serving units.
Thanks Stardock, for yet another great game improvment. LH continues to exceed my expectations.
P.S. Now if we could just increase the group sizes from the current maximum of 6 in a unit back towards the larger units we could research before all would be perfect.