https://wccftech.com/intel-raptor-lake-13th-gen-core-cpus-will-retain-ddr4-memory-support-in-addition-to-ddr5/

The successor to Intel's Alder Lake CPU lineup, codenamed Raptor Lake, is expected to retain support for DDR4 memory.

The latest information comes from Moore's Law is Dead who reports that Alder Lake buyers who are getting on board the DDR4 platform don't have to worry about their platforms going obsolete within a generation because Intel's Raptor Lake CPUs will retain support for DDR4 memory. So it looks like users who invest in a DDR4 platform now can upgrade to a Raptor Lake CPU when the new processors arrive a year from now.