When realvision gets an update, it will send a notification to nexus mod manager saying there is a new version.
When that happens I recommend using ENB FXAA SweetFX manager to remove all traces of the old ENB (all your saves and other mods will be unaffected)
http://www.nexusmods.com/skyrim/mods/7804/?
And then follow the instructions given in section 4 of the Realvision ENB description, just in case something changes with the install process.
http://www.nexusmods.com/skyrim/mods/30936/?