I want to write
"The date you are trying to write is not ... than the existing one."
when user wants to write and replace date in some document. Should I use "newer" or "later"?
Somebody has to overwrite 30.12.2018 with date, which is not earlier nor same as 30.12.2018, e.g. 31.12.2018. If he writes 29.12.2018 or 30.12.2018, I have to respond than the date he is trying to write is not later/newer than the existing one (30.12.2018). Which one should I use?
Replaced 'older' with 'newer', as @virolino mentioned in his answer.