Can i install 4.0 while keep using 2.1

As the title says,

I want to install/migrate to the latest version, but as it is a lot of work to install everything i want to keep using my current version (2.1).

Is it possible to install them next to each other ?

I would not touch anything on the 2.1 instance. No changes, no updates, and bullet proof and tested backups.

2.1 is basically unavailable thanks to the sunset of bintray and there are precious few left on the forum who can help with such an old version of OH.

Theoretically, you could run the two side-by-side. You would need to configure one of them to use a whole different set of ports though and since things may not work like network discovery from done bindings.

But there are serious practical problems you’ll likely face. For example, if you are running on Linux, if guess you are currently running on an old OS, like Debian wheezy. These older OS’s often can’t install Java 17 and OH 4 requires Java 17.

You do not want to try an in place upgrade of the machine where 2.1 is running. You need to treat that machine like a museum piece until you have everything transferred to the new insurance.

So I recommended one of two approaches, depending on your available resources.

  1. Set OH 4 up on a different machine

  2. Do periods of processing on the one machine. Prepare a separate boot drive or sd card or what ever, work on your OH 4 config, then when done for the day load up the old drive to run your home automation when not working on it. One version of this spiritual can be through a virtual machine.