Learn English – “one more step” or “one step further” or “one more step further”

Considering the audience aren't native english speakers, one or two people not too firm in the language might be irritated by "moving on", so make sure you express what's going on in the email's content, I suppose.

"Moving on" by itself is a very good choice, though, especially as it sounds a tad more positive than plain "Leaving", as user8543 mentioned.

(I'm only considering the interchangeability of further and more here, other meanings of further are no taken into account.)

1. Use "further" when you want to express some range or degree, either physically or metaphorically.
   
   Examples:

   • further research: include new aspects, new methods, new data....
   • further down the road: from your position, extend down the road.
     
     

2. Only "more" is correct, when you focus on a measurable amount, even with uncountable nouns.
   
   Examples:

   • more shoes
   • more coffee

   • more reputation on Stack Exchange
     
     Example in one sentence:

   • We need more money for further research.

3. On interchangeability:
   
   When both extension and countability are correct, you can use "more" instead of further, but usually "further" sounds more polished.
   
   Example:

   • We need more research. / We need further research.
   • Move a few inches more to the right. / Move a few inches further to the right.