From the looks of things, this anime is actually almost certainly something new, not a continuation of Vivid, and probably takes place in Vivio's adulthood. It seems to basically be the StrikerS of Vivid, and probably will NOT be focused on lolis.
There's a few big pieces of evidence for this:
1) Less than a year ago, Yukari Tamura, the VA of Nanoha herself, had a huge falling out with the record company that handles the series, so it's quite possible that she doesn't want to be involved with it any more.
2) The OP and ED are being sung by the VAs of two of the brand new characters (the VAs who voiced Carol in Symphogear GX and Rom in the Neptunia franchise), instead of Yukari Tamura and Nana Mizuki.
3) The logo in the teaser image just says "Vivid Strike: Thou shalt not be afraid I am with you", without the words "Mahou Shoujo Lyrical Nanoha", and the character in that image doesn't match the appearance of any previous character.
4) The cast list is missing quite a few characters who are important to Vivid, but also includes one character who first appears way, way later in the manga than where last year's Vivid anime cut off.
Also, thanks to 4chan, we now know what cars all the new characters are names after.
Fuuka Reventon = Lamborghini Reventón
Rinne Berlinetta = Berlinetta is a style of coupé.
Yumina Enclave (actually a manga character) = Buick Enclave
Jill Stola = Stola was an Italian company that designed cars.
This could either be a great revival for the franchise, or a massive trainwreck that's it's final nail in the coffin. Here's to being cautiously optimistic!