Marantz 8802 Vs 8802A As PrePro

Hello All, 

Considering an upgrade to my home theater preamp and looking at Marantz 8802 or 8802A Pre/pro. My setup is 4K TV and do 5.1 or 7.1 Surround. Sources are Apple TV 4K and Fire Stick 4k. 

Could you please advise what are the differences between 8802 & 8802A ? What would I wont be able to do if I go with 8802 ?

Thanks in advance for the help.