trying to update a pack while keeping my world

[deltawaves1]

hi all, i'm trying to update my FTB infinity single player world in 1.7.10 from version 1.8.2 to version 1.10.0 but whenever i do and try to get into my old world i get this error message:


could someone please tell me what to do to get these missing blocks?

may thanks.

Deltawaves1