Julia v1.0 is identical to the v0.7 release, with the exception that it removes all deprecations and deprecation related warnings. When upgrading a codebase from v0.6, the process is to first get the code to work on v0.7, and fix all the deprecation warnings. Once the code runs on v0.7 without warnings, it should be good to run on v1.0.
Refer to the Release Notes for v0.7 for a detailed list of changes from Julia v0.6.
The old package manager (now called OldPkg) has been moved to a
separate repository at https://github.com/JuliaArchive/OldPkg.jl (#27930)