I get this error after the recent updates.

The mod Concreep caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Concreep::on_nth_tick(60)
Unknown item name: 1
stack traceback:
Concreep/control.lua:151: in function 'creep'
Concreep/control.lua:29: in function <Concreep/control.lua:14>
stack traceback:
[C]: in function 'get_item_count'
Concreep/control.lua:151: in function 'creep'
Concreep/control.lua:29: in function <Concreep/control.lua:14>

I knew it wouldn't be that easy... This is caused by attempting to replicate the tiles under the roboport.

What tile-modifying mods are you running? (Dectorio, Alien Biomes, etc)

I could write a migration script to fix the internal data... Or since there's no items you have to worry about migrating, disabling the mod, loading, saving, then re-enabling the mod with v1.3.4 will also fix this.

Edit: Turns out I need a sort of migration anyway as this would crash if someone removes Dectorio mid-run. 1.3.4 will have a proper update so you won't need to do this.

The mods i have are
Aliend Biomes
Angels Addons Warehouses
Robot Attrition
Robot Battery Research
Space Exploration
Warehousing Mod

Disabling and re-enabling seems to have done the trick in my case. If you'd like a copy of the save I believe i have it pre-work around.