I think your actual problem has to do with character encoding, which has been raised/addressed here. I can't replicate your error message.
# set encoding
options(encoding = "UTF-8")
# packages
if (("geojsonio" %in% rownames(installed.packages()))==FALSE) install.packages("geojsonio"); library(geojsonio)
if (("geojsonlint" %in% rownames(installed.packages()))==FALSE) install.packages("geojsonlint"); library(geojsonlint)
if (("devtools" %in% rownames(installed.packages()))==FALSE) install.packages("devtools"); library(devtools)
if (("rgdal" %in% rownames(installed.packages()))==FALSE) install.packages("rgdal"); library(rgdal)
install_github("ateucher/rmapshaper")
# grab the file from "Statistics Canada"
url<-"http://www12.statcan.gc.ca/census-recensement/2011/geo/bound-limit/files-fichiers/gcd_000b11a_e.zip"
n<-basename(url)
download.file(url,
destfile = n)
unzip(n,exdir = substr(n,1,nchar(n)-4))
canada_raw<-readOGR(file.choose(),use_iconv = TRUE,encoding = "CP1250")
canada_raw_json <- geojsonio::geojson_json(canada_raw)
canada_raw_sim <- rmapshaper::ms_simplify(canada_raw_json)
still having the same error
Error: lexical error: invalid bytes in UTF8 string.
CDUID": "2485", "CDNAME": "Témiscamingue", "CDTYPE": "MRC",
(right here) ------^