[DiapDealer]

You can use the installer to install Sigil to any location you like. However, all installed versions will use the same preference files (*.ini) and thus the same preferences. Having multiple instances of Sigil open that are reading and writing to the same preference files can lead to unintended consequences--even with the same versions of Sigil. Never mind when using two different versions at the same time

We have, however, made it possible to define a different location for Sigil's preferences folder by setting an environment variable (SIGIL_PREFS_DIR) to point to a different user writable path to use for a preferences folder.

So you could run one version of Sigil normally and then create a batch (or .cmd) file that sets the SIGIL_PREFS_DIR variable before launching Sigil. That way you could have two completely independent versions of Sigil running on Windows. Each complete with their own preferences, plugins, appearance, etc...

The last Sigil installed will always be the one that launches from the Desktop shortcut, so you might have to create your own shortcut to the one you want.

Or if you want to try the new version of Sigil, you can also back up your current preferences folder somewhere and just install the new version. If you ever want to go back, just uninstall Sigil, reinstall the older version and restore your preferences backup and be right back where you started.