Is it still possible to upgrade an AMR DP-777 to SE?

I’ve had the DP-777 since last May and it’s by far the best sounding DAC I’ve owned so far. Never thought I’d end up with a tubed DAC but this one is a real joy to listen to. Well, we audiophiles never seem to be satisfied, and the reviews of the SE version of this DAC indicate that it’s a significant improvement over the original. For a time it appeared that the DP-777 could be upgraded to SE status, but now all the older AMR models seem to be listed as "legacy products" on their website, and as such I can’t figure out whether they’re even making these products any more.

Have any of you done this upgrade? I’d be interested to know how it worked out for you. I’m considering having this done if it’s still possible. I’m in the USA so shipping the thing to England is not really an option even if they’re still doing these upgrades, but perhaps there’s an authorized AMR tech in this country who can do this?