>For a while, I think it was in 70s, Germany opted for alternate spelling of the umlauts with the vowel sans umlaut followed by an E, so ä, ö and ü became ae, oe, ue - because there were too many computers and teleprinters out there that had only 26 characters. Probably happened while you were there.
This alternate writing is still very common with crossword-puzzles. You will hardly ever use "ü" directly in a square - you are to put "u" in one square, and "e" in the next.
I assume that otherwise, it would be too difficult to make the words fit.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)