I'm sorry, I wasent at my computer(still isn't, though don't have my ubuntu VM anymore neither anyway) and previously found lines from searching old post of mine, but took one all way back from 2019 stupidly as first hit in google(and was for libtorrent 1.1 so I changed it to 1.2, but it had a hyphen less which I didn't know), sorry.
Thank you very much for your help.
Now my libtorrent version is 1.2.14 but why the libtorrent site says the last version is 2.0.4?
I can move my torrents now.
Newest libtorrent indeed is 2.0.4, but deluge doesn't support libtorrent 2.0.x yet, though libtorrent 1.2.x still gets bugfixes, possibly new development also, or atleast was like that previously i.e after libtorrent 2.0.3 then 1.2.14 released, followed by 2.0.4, so you're on latest deluge supported libtorrent version currently.