Mid 2007 iMac cpu upgraded from t7700 to t8300 and now I have Mojave : r/mac
2nd HDD SSD Caddy for Apple iMac Mid-2007 20-Inch Desktop Computer A1224 Core 2 Duo 2.0 2.4 MA876LL MA877LL, Second 2.5" Hard Disk Drive Enclosure Adapter, CD DVD SuperDrive Optical Bay Replacement :
How to install an SSD into an iMac (2007-2013) | Zollotech