You can access previous releases by modifying the URL of the *.zip download. The zip archives are named st_stm32_1.x.y_win.zip where x is the major version and y the minor (bugfix) version. The latest bug-fix release for each major version is st_stm32_1.0.2_win.zip and st_stm32_1.1.1_win.zip
The hosting of these files is subject to change, but you can always reach out to firstname.lastname@example.org if you encounter this in the future.
Also note that with a permanent license you are entitled to all bugfixes associated with the last major release when your license expired. If your license works for 4.5.6, then it will also support up to PLECS 4.5.9, and therefore the 1.1.1 release of the STM 32 TSP.