trials or free versions that can open PDFs limited in size, such as DiffNow (which was suggested in one of the linked answers). I have documents that are 20 MB or larger.
The PDFs in question are in general similar with respect to text. I expect only little changes. However, visual comparison is not possible, since adding a sentence may move all subsequent content to a new page.
I have tried:
copy/pasting the text of the PDF and using a Diff-Tool like Winmerge. However, that resulted in issues with special characters such as ß and also with line breaks. Also, in the end it's hard to find out on which page that difference is.
the question Free PDF comparison tool, but it has been asked for OS X and I need it for Windows. I have tried some of the tools that work on Windows as well,
Note: Diffpdf compares the PDFs page-by-page, so it won't work as well if the changes have moved a paragraph to a different page. There's a couple ways to work around this:
You can specify which pairs of pages to compare. For example, if a paragraph has moved from page 2 to page 3 in the new version of the file, compare page 2 with page 3 in order to compare that paragraph.
You can use this bash script to convert both PDFs to a single-page "scroll" before comparing them. (You can run bash scripts on Windows 10 using wsl.exe)
I'm currently adding pdf support to my diff. Its not free but fairly cheap at $19. I have it working with some test pdf's but if you want to try it with your pdf's please contact the support email on my site and I can make it available to you. See AJC Diff