Another problem I have with my OKMs are noise interference by mobile phones.
Does anybody know if the DPAs have a similar problem?
I think most new mics will be better than your old mics, but still turn off your phone. Lacking any actual testing data, I would look at it this way... about 5 years ago AT853's came out with a new model (U853) with the specific idea that it was less RF sensitive. Other makes have made similar changes, they're just less obvious about it. Mics like DPA's and B3's are primarily marketed as lavaliere mics for actors and TV news people wearing wireless belt packs. I think it's reasonable to assume newer mics probably have better shielding than an older set of mics, "older" meaning ones that were made before the cell phone and wireless mic boom of the last few years.
Most larger gear with balanced connections (typically XLR connectors) has less issues with RF because the same noise gets infused on both the positive and negative leads, so it cancels out. That doesn't help you, but I just thought it was worth mentioning.
I like AT853's myself... There is almost always a set in the yard sale at very reasonable prices. Make sure they have the "low sensitivity mod" or they will brickwall like your first mics.