I just received an email from Apple that states:
On February 14, 2016, the Apple Worldwide Developer Relations Certification Authority Intermediate Certificate expires and receipt signatures will include a renewed intermediate certificate.
Since you may use receipt validation in your apps, we want to make you aware of potential issues your users may encounter due to the renewed certificate. Users running OS X El Capitan (v10.11 or v10.11.1) may receive a notification that your Mac app is damaged if it utilizes receipt validation to request a new receipt from Apple. They can resolve this issue by restarting their Mac or updating to OS X El Capitan (v10.11.2) or later. Mac App Store customers running OS X Snow Leopard (v10.6.8) will be unable to purchase new apps or run previously purchased apps that utilize receipt validation until they install the Mac App Store Update for OS X Snow Leopard which is available via OS X Software Update.
So essentially you either need to upgrade to the latest OS update available to you or reboot your Mac if you get an error stating that Tap Forms is damaged when you try to launch it after this date.
The last time this happened I received hundreds of emails from customers telling me that my update caused Tap Forms to fail to launch. But it was not from something that I did. It was due to this certificate issue. This time Apple has given us all fair warning and I'm passing this information on to you so that you understand what happened and how to correct it.