My old iPad Pro 10.5 was downgrafe if it was updare security.

when Apple update security the old devices iPad Pro 10.5 but Apple downgrade functions device ? My iPad Pro 10.5 got too many pronlem when I use “reader” on Safari. When I turn on “smart invert” all photo (pictures) look like negative film. If I use other app then return Safari “reader” the reader is blank.