I have several of the foil lined packages of Microdol-X which my Dad bought in the 70's. I recently mixed one to develop a roll of Minox Agfapan 25 from 1986. Beautiful negatives!
The film had always been in the freezer so it was fine, and the Microdol-X was white, and mixed clear.
I'd say use it if you have a special film. I still think it was the best fine grain developer ever.