Any projects which want to use Hush code from now on will need to be licensed as
GPLv3 or we will send the lawyers: https://www.softwarefreedom.org/
Notably, Komodo (KMD) is licensed as GPLv2 and is no longer compatible to receive
code changes, without causing legal issues. MIT projects, such as Zcash, also cannot pull
in changes from the Hush Full Node without permission from The Hush Developers,
which may in some circumstances grant an MIT license on a case-by-case basis.
The wallet now only stores Sapling extended spending keys, and thus can
only be used with keys generated from an HDSeed via ZIP 32.
Note that not all Sapling keys in the wallet will correspond to the
wallet's HDSeed, as a standalone Sapling xsk can be imported via
z_importkey. However, it must have been generated from a seed itself,
and thus is more likely to be backed up elsewhere.