An upgrade to the low energy 201.25 MHz Linac at Fermilab is described in this paper. The upgrade to the low energy Linac system has been implemented to improve cavity vector regulation and reduce beam losses. The upgrade includes an adaptive feed forward system for beam loading compensation, a digital phase feedback system for the RF, a digital phase comparator for cavity tuning, and a low level RF system that is digitally controlled and referenced to a very stable 805 MHz reference line.