Package impossible to load

Hello, my name is mondesir and I am a geographer cartographer. I know a little bit about programming on R. I am writing to you because I have a problem with my package tmap. It doesn't work and here is the error message I get

library(tmap)
Error : package or namespace load failed for ‘tmap’ in readRDS(ffile):
unknown input format

What should I do? I need this package to work