Extended features being disabled

[Ed386021426ikq]

I download a file pptc054.pdf from 

https://www.canada.ca/en/immigration-refugees-citizenship/services/canadian-passports-usa/renew-us.h...
Using Firefox 78 on my iMac running MacOSX 10.9

and attempt to edit form fields using Adobe reader 11.0.23 but it immediately sends dialog saying file has been modified , therefore extended features are disabled. Ask author for original file.  And nothing can be entered.  What's happening?

[kglad]

in the future, to find the best place to post your message, use the list here, https://community.adobe.com/

p.s. i don't think the adobe website, and forums in particular, are easy to navigate, so don't spend a lot of time searching that forum list. do your best and we'll move the post (like this one has already been moved) if it helps you get responses.

<"moved from using the community">

[try67]

You should try a more up-to-date version of Reader. Also make sure not to open the file in the browser and then use Save As, but to save it directly to your computer via the link, and then open it in Reader.