Samsung SSD with Catalina or Mojave I have High Sierra installed from a USB bootable drive on a Samsung SSD
(Samsung MZ-76E500B/EU 500 GB 860 EVO Sata III 64L V NAND Solid State Drive) but I need XCode and that needs to be on Mojave 10.14.4+ and because i have a third party SSD the app store blocks me from upgrading. 

So I put a Catalina beta on a USB drive but when I load up the iMac holding option and select the drive I just get a cancel symbol. 

Not sure what to do to get a more modern OS on this SSD? Anyone had any luck with Mojave or will that be the same?

Thanks in advance
It would appear the issue is with compatibility, it is a Mid-2011 27 iMac so no longer supports Mojave or Catalina

https://eshop.macsales.com/guides/Mac_OS_X_Compatibility

Damn.