https://www.engadget.com/babylon-5-remastered-hbo-max-digital-download-080058907.html

Color me surprised, I thought this was never happening. It says they rescanned film negatives for all 5 seasons at 4K and then scaled it down to HD. The took all the CGI and composite shots (live action with special effects) and simply upscaled them from SD to HD. I would think you would see a noticeable difference between the two. It's all being done in the original 4:3 format which is probably for the best.

The pilot movie The Gathering could not be remastered since the original films were lost. The article does not mention any of the B5 movies or Crusade.

The Gathering in SD and Babylon 5 seasons 1-5 in HD are going to be streaming on HBO Max.