'Keeping up-to-date on' or 'Keeping up-to-date with'?

I recently replied to someone who was informing me about my application for something. I replied "Thank you for keeping me up-to-date on my application". Afterwards I wondered if I should have written "Thank you for keeping me up-to-date with my application".

Which is grammatically correct?

If you are a job applicant, and corresponding with someone at a company that is considering hiring you, neither on or with is correct, and the phrase up-to-date is a little too casual. Thank you for keeping me updated about the status of my application, or Thank you for updating me about the status of my application would be more appropriate. The first of my suggested rewordings would be appropriate if you have been updated more than once; the second, if only once.

I hope this helps.

You might use on for a topic ("keeping up to date on politics"), and with for a source of information ("keeping up to date with the television news") or an ongoing task ("keeping up to date with the housework"). For a particular matter, you'd keep up to date about it, which is what you want here.

You might also prefer informed. "Thank you for keeping me informed about the status of my application".