CPU selection

Dear experts! I have a question regarding S7 processor selection. Currently I'm using S7-317-2PN/DP CPU with approximately 50% assigned Work Memory and the same amount Retentive memory data. My question - what would be appropriate CPU from 1500 series? For new processors there are terms "Work memory for program, integrated" and "Work memory for data, integrated". Is the second one the same as "Retentive memory data" in S7-300 CPU?

Is there any method for selecting the CPU based on number of IO's and approximate number of code lines?

"Work memory for data, integrated" is not the same as "Retentive memory data" in S7-300 CPU. You can find the amount of retentive data supported by 1500 CPUs in the technical data of each CPU in the following manual collection:

https://support.industry.siemens.com/cs/ar/en/view/86140384

In chapter 5 of each CPU you find the following information (this one is from CPU1516, which is probably the CPU you may choose):

Data areas and their retentivity

Total retentive data area (including timers, counters, bit memories), max.

512 KB; for bit memories, timers, counters, DBs and technological data (axes), usable retentive memory: 472 KB