MUNI Rollsign Quesiton

I noticed some of the MUNI trains have rollsigns and the others have digital signs, is there any rhyme or reason for that? They all look like they are from the same era.

Gradual changeover from roll signs to digital signs?

Such a changeover was done in Boston for one series of light rail cars (Kinki Sharyo). The newest ones (Breda) came with digital signs.

MUNI received two separate orders of Breda LRVs. The original group, 1400-1475, which MUNI refers to as "LRV2", were delivered with roll signs. The second group, 1476-1550, aka "LRV3", were delivered with LCD digital destination signs. There seem to be a few LRV2s which have been retrofitted with LCD signs, but there are still plenty with roll signs which were even updated when the Third Street line was completed.

My hand-built rollsign case for my working Muni rollsign.