How to migrate to EPCQ64A from EPCS64 with Cyclone III FPGA?

Hello Oliver, If your design do not contain IP Cores (which interface with the config device), your existing programming files may be compatible with EPCQ-A devices without the need to regenerate the programming files. Refer to Table 3 on page 6 for more details. If you design contain IP core, please refer to Table 1 & Table 2 (on page 5) for the IP core compatibility. https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/an/an822.pdf I hope this will help. Thanks