Many packages don't work under R version 4.0.2 although they worked fine in previous versions.

I am using RStudio. I updated my R version from 3.6.1 to 4.0.2 and since then many packages won't work. I am getting the following messages. What can I do to fix this?

> library(EEM)
Error: package or namespace load failed for ‘EEM’ in loadNamespace(j <- i[[1L]], c(lib.loc, .libPaths()), versionCheck = vI[[j]]):
 there is no package called ‘vctrs’
> data2 <- readEEM(getwd()) 
Error in readEEM(getwd()) : could not find function "readEEM"
> library(readxl)
Error: package or namespace load failed for ‘readxl’ in namespaceExport(ns, exports):
 undefined exports: excel_format, excel_sheets, format_from_ext, format_from_signature, read_excel, read_xls, read_xlsx, readxl_example, readxl_progress

Each version of R you have installed maintains it's open library of packages. When you install a new version of R you must re-install any packages you intend on using.

If you are going to keep your old library or copy your packages to the new location you have to update your packages with checkBuilt = TRUE

update.packages(checkBuilt=TRUE)