Version 2.12+ of BookMacster, Synkmark, Markster and Smarky require macOS 10.14 to run. This unfortunate surprise is due to a bug in Apple's latest developer tools. Apple still has not fixed the bug, and judging from our past experience with bugs of this kind, they will never fix it. We considered working around the problem by building our apps with an old version of Apple's developer tools, but…
• Building with old tools always causes more bugs in the long run.
• The special build process will divert resources from our moving forward.
• The changes in 2.12 vs. 2.11 are mostly beneficial to macOS 12 users.
• Version 3.0 of our apps, now in development, will require an even later macOS (macOS 11) anyhow.
So we decided to change the system requirement for BookMacster, Synkmark, Markster and Smarky to macOS 10.14, effective with version 2.12. Users with macoS 10.13 or earlier should continue to use version 2.11.8 of our apps. Or, for BookMacster, you may want BookMacster 2.11.11. BookMacster 2.11.11 has less user hours on it, since we never published it out of beta. BookMacst 2.11.11 has some small bug fixes, particularly for synchronizing with Pinboard and Diigo.
Here are the links for those who need to redownload these old versions: