Sorry, now i have some time again. I understand I should read, what should I read if I would replact Caecilia (I like the condensed version) with Constantia, and that's all. (As embedded font it works fine.) I have no problem in installing several packages, I just don't know what can go wrong and how should I fix it
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I know I hardly understand things, I just wouldn't like to brick my device in any case.