Short answer is: no, there is no easy way to transfer the project.
Faking the version number still works, just as same as back then. However this has the limitation that if there were changes to the model that are not backward compatible e.g. conditional visibility expressions, the older modeler simply can not read the model properly.
If it is a small project your best option is to redo it.
If this is just too much work (> 1 week) you might consider investing some time in the mendix sdk. It can read the model from version 7.8 and recreate it in any version you like. You will probably not be able to migrate everything but the bulk of your domain model, microflows and pages you should be able to migrate with some effort. It is actually simpler than it sounds because the sdk comes with a handy function that takes in a microflow for example and gives you a code that you can invoke in order to create that same microflow in another module or even project
You can read more here: https://docs.mendix.com/apidocs-mxsdk/mxsdk/generating-code-from-the-model
https://forum.mendix.com/link/questions/92646 tells me about mprTool.exe in the modeler's program-files directory: Mendix\7.13.1\modeler