I’m trying to open a file made with dynamo 2.12 in dynamo 2.3 but it just opens an empty project. It is a pretty complicated script I don’t want to redo from scratch. I’m totally ok with replacing a few nodes due to mismatching package versions but it not even opens.
I’ve been opening graphs written in 2.13 in 2.1 for much of my day… My guess is your Dynamo 2.3 has a conflict which is causing nodes to not process. Can you check your notifications?
I just have checked the notifications and seems like archilab is not backwards compatible. I will try to use the same version in both then. However the version is incorrect in the notification I use a much more recent version not 2018 
While loading assembly archilab, Version=2018.0.0.1, Culture=neutral, PublicKeyToken=null, Dynamo detected that the dependency RestSharp, Version=106.6.10.0, Culture=neutral, PublicKeyToken=598062e77f915f75 was already loaded with an incompatiable version. It is likely that another Revit Addin has loaded this assembly, please try uninstalling other Addins, and starting Dynamo again. Dynamo may be unstable in this state.
It is likely one of the following assemblies loaded the incompatible version:
GregRevitAuth, Greg, DynamoPackages
You need to install the right version of archi-lab for your Revit build. Check the last two digits of the build as per the link in this reply.