If you want a quick fix open up the mod and put this at the end of data-final-fixes.lua.
I will properly patch and test later.
local belt = data.raw["transport-belt"]["express-transport-belt"]
if belt then
belt.next_upgrade = nil
end
local ubelt = data.raw["underground-belt"]["express-underground-belt"]
if ubelt then
ubelt.next_upgrade = nil
end
local splitter = data.raw["splitter"]["express-splitter"]
if splitter then
splitter.next_upgrade = nil
end