The linear accelerator REGAE (Relativistic Electron Gun for Atomic Exploration) at DESY delivers electron bunches with a few femtosecond duration for time-resolved investigation of material structures in a pump-probe configuration. To achieve a sub-10fs resolution, the Low Level RF controls for the normal conducting S-band cavities, must provide field stability of .005% in amplitude, and of .005 in phase. To achieve these demands, the recently developed LLRF control modules based on the MicroTelecommunications Computing Architecture (MTCA.4) platform will be used. For precise field detection and control, a rear transition module (DRTM-DWC8VM1) housing 8 down-converters and 1 vector-modulator has been developed. The downconverted signals are transmitted to low-noise ADCs on an advanced mezzanine card (SIS8300L) with two high speed DACs driving the vector-modulator. The on-board FPGA device runs the advanced control algorithms with minimum latency. Shot-to-shot learning feed forward and ultra-fast analog and digital feedbacks are applied. In this paper, the new hardware platform is described and the proposed algorithm is discussed.