Admin roles: the two of us exchanging messages, and a 3rd admin just in case, if something goes terrible wrong.
SMF 2.0.17 works like a champ on a humble RPi@700MHz/256MB RAM, and from an SD card! 
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The above text is from this post:
https://www.eevblog.com/forum/general-computing/a-smf-forum-as-a-personal-platform/msg3216058/#msg3216058It looks like the last + character from the thumb up's emoticon : - + is showing correct when editing, but mangled after posting, so in the end there is no visible thumbs up emoticon published.
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LATER EDIT:
Hmmm, very weird, here it all seems to be working just fine, but not in the linked post, for some reason

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LATER LATER EDIT:
Found it. That post has had an iframe mention that deletes each and any + character after hitting Post.