In a blog post, Apple has acknowledged a problem with the autocorrect feature in iOS 11.1 that is replacing the letter “i” with an “A” accompanied by a symbol. So far it’s the only autocorrect problem that Apple has specifically addressed, but we’ve seen other problems as well — like the word “it” being converted to “I.T.” or “I’d” being changed to “I.D.” — and there’s an entire Reddit thread dedicated to the issue where users have seen everything from strange capitalization suggestions to missing punctuation fixes like changing “im” to “I’m” as it usually does.
For the “I” problem, Apple’s post suggests a software fix is in the works, but also suggests a quick workaround in the meantime.

The company suggests going into Settings > General > Keyboard > Text Replacement, the tapping the plus sign to add an entry. Then in the “Phrase” field, add an “I” and in the “Shortcut” field add an “i.” Manually adding autocorrect fixes that are coming up wrong has also worked for some users experiencing problems, but have also shown signs of reverting back to the problematic behavior, so hopefully Apple rolls out a more permanent fix soon.
.