A lot of DDLC and Ren’Py mods were written for Ren’Py 7 and Python 2. Ren’Py 8 runs on Python 3. Strings stopped being interchangeable with bytes, syntax shifted, and scenes that “always worked” crash on launch or fail in a late branch. Doing that migration line by line is possible. On a large mod it is also a weekend you will not get back.

R-Migrator batch-processes a project directory and applies the boring, repeating fixes so you can spend time on the weird custom code the tool will not guess.

What it actually does

common Python 2 / Python 3 incompatibilities;
bytes / str problems that show up the moment you boot the game;
automatic unpacking of .rpa and .rpyc before patching;
typical DDLC-mod trouble spots;
directory-wide processing instead of opening files one by one;
faster scans on large projects thanks to Cython compilation.

It is not a guarantee. After the automatic pass you still test, especially anywhere the original author wrote one-off Python.

In the pipeline

R-Migrator — get the old project running on Ren’Py 8.
RenDoki — prepare localization.
AutoBuild — assemble a build you can ship.

v1.1 shipped on 8 September 2026. The first public beta was completed on 9 May 2026. It was the first public piece of ROOTWIN’s newer DDLC/Ren’Py line.

User guide

A full walkthrough of the interface, the .bak backup option, automatic .rpa/.rpyc unpacking, and the whole migration flow is available on a separate page: R-Migrator user guide.