We have been wanting to do AND conditions as well and I reported this as well earlier. You can't do multiple rules from the same header, etc.
With a regexp, there’s just one condition line for “Subject” in one rule.
You obviously know more than I about how this is working on the backend. I didn't know there would be a limitation to the number of matches to header filters you could have as part of one rule, but I am not a regexp expert either.
I’d probably set two different rules/filters, a “Hello.*World” and a “World.*Hello” …
Yes, I ended up creating two rules in one instance I was trying to solve as well. I think I was running up against wanting to check for the existence of one thing in the header (body) and the absence of another item in the same header (I actually was using the body). Is there a way to do that if I create multiple rules? I am rather new to otrs, so I am still learning the background, etc. I didn't see a way to reorder rules either though I haven't needed to use a case that required rules be applied in a certain order yet. Is there a way? Thanks for your insight.