Port PIC code for out of stock/date model to newer model

Assistance needed in porting code written for a PIC18F26K to a more modern model (that is in stock). Program is about 400 lines of C, I suspect the model number may need to be changed and a few pins remapped, but otherwise the code is usable. Currently using 1 A/D, TX/RX for serial and 4 GPIO pins. The code is doing battery management. If it is less time the code could be ported to Atmel or Arduino if decided, it is not doing a whole lot. Bonus points if you are familiar with Raspberry Pi. This project sends data via serial to the Pi and that also needs some updates. Can discuss that further after this is completed.