I am testing the usage of Posit's package manager as a substitue for MRAN and cannot find binaries for arm64 architecture on Posit, while I do find it both on CRAN and MRAN for the same date.
Code below shows that source packages are found on packagemanager but not binaries, and that those binaries are available from mran and cran. This code runs fine in windows because those binaries are found, presumably it would run also in Linux and older Mac, the problem is with arm64 binaries.
#1 binaries found on cran
ap = available.packages(repos='https://cloud.r-project.org/', type='binary')
dim(ap)
#2 But not on packagemanager with a specific date
ap2 = available.packages(repos='https://packagemanager.rstudio.com/cran/2023-01-12', type='binary')
dim(ap2)
#3 nor with the most recent
ap3=available.packages(repos='https://packagemanager.rstudio.com/cran/latest',type='binary')
dim(ap3)
#4 But they are found on MRAN
ap4=available.packages(repos='https://mran.microsoft.com/snapshot/2023-01-12',type='binary')
dim(ap4)
#5 And the source file are found on posit
ap5=available.packages(repos='https://packagemanager.rstudio.com/cran/latest',type='source')
dim(ap5)