You could try to make a copy of your save files to transfer them. you would have to find which folder your device stores roam data, ren'py uses that folder to store saves that then can be retrieved by the next update without you having to tell it to. That said, I did have to manually go through many of the previous lines this update when attempting some reruns.
Alternatively, you could go to the in game setting and activate "unseen text" in the skip options, but make sure you deactivate that once you catch up do a few more lines and save. If you forget that option is on, you could easily come across something you haven't seen and skip it by accident.