Treecell is a commercial software.

You may copy or distribute Treecell provided
that it's an unmodified and complete version, as downloaded from
https://www.japplis.com/treecell/ or from Chocolatey package manager
or from the Mac App Store or from Microsoft Store or from Canonical Snap Store.

After the trial period or the free usage allowed per month, you need a 
user license per user of the software. The same user license can
be used on 2 computers/VMs if the same physical person is the main user of
the software on both computers/VMs. For example having the software on a 
professional and a personal computer. Also one user license can be used by 
multiple physical persons if used on the same physical personal computer.

It is not allowed to use Treecell or its data in a SaaS (Software as a
Service) or as a library of another software.

THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT WARRANTIES WHETHER EXPRESSED 
OR IMPLIED. THE AUTHOR SHALL NOT BE LIABLE FOR ANY DAMAGE RESULTING OF THE
USE OF Treecell.

It's prohibited to decompile the code.

Treecell is released with libraries which have other licenses.
The list of the libraries and their licenses are listed in 
Help -> About -> Licenses -> Third-Party libraries.
