Cannot convert COMPADRE with R 3.5.2

I tried to convert COMPADRE / COMADRE locally to build the doc and got the following error message when running main.R

Error in load(url("https://www.compadre-db.org/Data/ComadreDownload")) : 
ReadItem: unknown type 115, perhaps written by later version of R
Execution halted

I'm using a slightly outdated version of R (3.5.2), but it's the default one in Debian stable. I guess upgrading R will fix the problem for me.

If I understand correctly, the reason for this is that, even for such simple data as those in COMPADRE/COMADRE, the RData format is not stable?... 🤦