Get past the first-open security prompt for the menu bar calendar with Open Anyway, or a right-click on macOS 14, until Blipcal is notarized.
The short version
Double-click Blipcal in your Applications folder. Until it is notarized, macOS says it cannot verify the app. That is expected, and it happens once per Mac.
Open System Settings > Privacy & Security, scroll to Security, and click Open Anyway next to Blipcal. Confirm with Touch ID or your password. The button appears after a blocked attempt. After that Blipcal launches normally every time.
On macOS 14 Sonoma you can instead right-click (or Control-click) Blipcal in Applications, choose Open, then click Open again in the dialog. macOS 15 and later removed this shortcut, so there it is Open Anyway only.
Blipcal is code-signed, and every update is signed with our key and checked by Sparkle before it installs. The prompt is simply how macOS treats apps from outside the App Store that are not yet notarized by Apple; it is not a sign that anything is wrong. Updates delivered through the app do not ask again.
See the download page to get Blipcal.
Still stuck? Email support@blipcal.com and we will help.