courieR - Migrate Installed R Packages Between R Versions

Detects all R installations on the current machine and migrates installed R packages between them. Provides find_routes() to discover R versions, manifest() to scan package libraries in a child R process, inventory() to compare two libraries, and ship() to install packages into a target R version using 'pak'. Includes a Shiny dashboard (open_hub()) for interactive source-to-target migration.