Are you referring to the x86 build and not the community ARM builds? If so, it looks like latest is set at 2.13.3 however you can pull 2.13.5 as server:2.13.5-beta.

If you are talking about the ARM builds, florider89's ARM server image for 2.13.5 appeared 15 hours ago, however etechonomy's has yet to be published.