It is no longer considered safe to can pumpkin puree. Pumpkin should be canned in 1" chunks for consistency in cooking and only done in a pressure canner. Now I can my pumpkin, using instructions from the National Home Food Preservation website. To make my puree and remove as much water as possible I have started using my Kitchen Aide Mixer and the attachment for skins and seeding. It does the best even puree that comes out one end while pulling the water into a bowl on the other end. A perfect puree for pies. I have been canning pumpkin for years and have 7 sitting in the living room right now to take care of in the next week or so, after halloween with I can take a breath.
Here is the web page for canning pumpkin:
https://nchfp.uga.edu/how/can_04/pum...er_squash.html