Oasis Mac Installer Can't be Opened Because Developer is Unidentified.
If you get this error, it is due to App Store restrictions/security settings. You can adjust the security settings to allow for all applications. However, if you don't want to do that for security reasons then take the following steps:
Hold Command and then Right Click on the install file you downloaded. Then click Open.
Then you will be asked if you are sure you want to open it. Click Open again.