R4 HELP

Hi, I have got 2 R4s. Bought one in Oct 07 and one in Nov 08. Both of them worked well up to now, when I put any latest games (above 2300) the games do not work and I get a message saying couldn't find the save data. I have tried to upgrade the firmware but anything above 1.16 wouldn't work. Now, I think maybe the R4 cards are too old ? Am not an expert in computer and things like that, just a mum trying to put games on the R4 for the kids.
Can anyone help? I have tried for many weeks now, thought I would have to buy new R4s, but what if it doesn't work?
Thank you
A

The newer R4 will be a clone, not an original, and thus will probably not use the same firmware as the original. The one you bought first is likely an original and should be upgradable to 1.18

Thank you for your reply. However, why do old games play on the R4 if it is a clone? how do I know when I buy an R4 if it is a clone? Which R4 do I need to get to put latest games on? thanks

the good clones (some are more compatible than others) are completely backwards compatible with old games. All R4 devices on the market are clones, it is no longer possible to buy an original R4 and hasn't been for at least 5 months. An original R4 with YSMenu (an alternative firmware) can play most new games so far. The compatibility rates of the clones vary, however providing firmware updates are still being produced for it, it should be able to play all or virtually all new games.

Older games have a higher rate of being compatible obviously because of older ARM7 files included with them. DSTT's compatibility is better than the R4's, so YSMenu is pretty much better, although quite a few homebrew and nearly all patched ROMs don't work.