Currently, the supported devices are 16F1507, 16F1508, 16F1509, 16F1825 and 16F1829 with LF variants for the latter two.

Though I'm planning to add more devices, you may want to try it by yourself. For basic PIC16F1xxx devices, you have to add new lines into setCPUtype function in pp2.c file. Each MCU has its descriptor, looking like

if (strcmp("16f1507",cpu)==0)
{
flash_size = 4096; //bytes, where 1word = 2bytes, though actually being 14 bits
page_size = 32; //bytes
devid_expected = 0x2D00;
devid_mask = 0xFFE0;
}

It is determined by four parameters:

flash size - its size is in words, where one word is calculated as two bytes, though the single program word occupies only 14 bits.

page size - this is the biggest chunk of FLASH that can be written at once.

devid_expected - clean device ID, where revision is chopped off

devid_mask - mask to be AND-ed with word from address 8006h to get clean device ID.

Say you want to add PIC16F1503. Download the datasheet and if you are lazy, search for "Device ID" string. One of the first search results should get you to the chapter 4.6, named Device ID and Revision ID

You can see what revision looks like, so lets create mask to chop off, where revison bits are

0010 1101 111x xxxx - ID register, where x are revision bits
1111 1111 1110 0000 - MASK to leave ID untouched
F    F    E    0    - MASK in hex format
0010 1101 1110 0000 - ID register without revision bits
2    D    E    0    - ID in hex format

The device ID translates to 2DE0 hexadecimal and mask to FFE0 hexadecimal. Now we have to determine FLASH size and page size.

In the same datasheet, go to chapter "Flash program memory control", or search for "latches". You should find chapter 10.2, where is described size of erase and write block.

The write latches buffer the data to be written into FLASH, so our page size is as big as amount of latches. Because flash is erased in bulk, write latches are interesting - there are 16 words of write latches, making 32 bytes of FLASH write "buffer".

Flash size is easy to determine, on second page of datasheet is comprehensive table

where PIC16F1503 has 2048 words of FLASH, translating into 4096 bytes. So, complete entry for PIC16F1503 should look like this

if (strcmp("16f1503",cpu)==0)
{
flash_size = 4096; 
page_size = 32;
devid_expected = 0x2DE0;
devid_mask = 0xFFE0;
}

Recompile, run and enjoy.