I recently just tried to download the Mojave OS on my iMac. It tells me "This version of macOS 10.14.2 cannot be installed on this computer". My iMac is a 21.5-inch, Late 2009, 3.06 GHz Intel Core 2 Duo, 4GB Memory. Since my computer is a little older I am not able to download another new Operating System? Is this correct Apple won't let me put Mojave on my system? Just trying to get some feedback on this. Appreciate it guys!