Fortunately or unfortunately, depending on your point of view, I have never had to do that. I do find the much easier FSRx and tables a real boon. Also, the added instructions and direct access to WREG have been appreciated. The 12F1840 has replaced the 12F683 as my simple chip. I like the 16F1829 too. I have not gotten into the newest versions like the 16F18857. I am still wed to MPLab 8.92, so some new stuff is not available to me. I plan to change that in the future.
John