- You can use Barrier which is almost similar to Synergy 1.9. It's actively maintained (receiving bug fixes) as an open source project. But it doesn't have digital certificates on binary releases.
- You can use Synergy 1.9.0-rc3 or 1.8.8 from some github repository. It's not maintained as Symless is working on Synergy 2.x.
References:
- https://github.com/debauchee/barrier Barrier is KVM software forked from Symless's synergy 1.9 codebase (some time before release v1.9.0-rc3, commit 54632e2 on May 9, 2017)
- https://github.com/amankhoza/synergy-binaries Synergy 1.9.0-rc3 and 1.8.8 (Win, Mac, Linux)
- https://www.brahma.world/synergy-stable-builds/ Synergy 1.8.8 (Win, Mac, Linux) (source code: Latest commit ec56ac4 on Mar 3, 2017 at https://github.com/brahma-dev/synergy-stable-builds)
Barrier is a fork of Synergy, and it's well maintained since 2015. We should use it instead.
https://github.com/debauchee/barrier/graphs/contributors