OK, I'm looking at the ad in the June 2015 issue of Lost Treasure magazine for the F11, F22, and F44. Some of the statements above are a bit off.
These detectors are derived from the same platform as the Teknetics 'Frat Brothers', i.e. Delta, Gamma, Omega and the Fisher F5. Being 'derived from a common platform' doesn't mean that they are just a 're-packaging job', these do have a different feature set and may perform quite differently. No doubt that the software has been changed a good bit, the physical packaging and user interfaces are different, and they operate off 2 AA batteries in a slide in pack (that's 3 volts instead of the previous 9 volts). Operating frequency is 7.69 Khz, like their 'Frat Brothers' cousins.
The F22 looks like a replacement for the F2. 9 Segment visual ID, numeric target ID, Fe-Tone adjustable Iron Audio (sounds like the EuroTek's feature). 4 'Modes' of Operation: Jewelry, Coin, Artifact, Custom. It is also 'weatherproof' and has a 9" triangulated concentric coil (somewhate egg shaped). If I'm remembering correctly, the F2 was available for about $200 minimum advertised price so I'm guessing the F22 will be priced a bit higher.
The F11 slots below the F22, lacks numeric target ID, Iron Audio, the Custom mode of the F22, has 4 tone audio ID and a 7" coil. It doesn't say anything about it being weatherproof. I would guess it will come in below the F2 in price.
I don't know that the F2/F4 will immediately be discontinued. FTP has continued models in the Bounty Hunter line long after they introduced models that could have been replacments, so it could happen with the Fisher lineup too.
Now the F44 looks like the replacement for the F4. It has all the features of the F22 and adds a Manual Ground Balance as well as Computerized Ground Grab Balancing.
The coil goes up in size to an 11" triangulated concentric. The display shows some interesting features the ad doesn't highlight. For one, it appears to have a display backlight. There is a depth indicator with more resolution that the F22 display. There is a mineralization display. There are 'Boost' and 'Notch' selections (those sound like promising features; perhaps 'Notch' is the variable width notch feature like that on the Bounty Hunter Land Ranger Pro, which is also built on the same design platform). Another 'Mode' is added to the F22's list, that being 'All Metals'.
I expect these machines are compatible with the previous 'Frat Bros' coils, specifically the screw-on versions. The F44 prototype was definitely screw-on, probably the F22 as well, just not sure about the F11.
Of course the proof is in how well they perform. They certainly seem to be feature rich detectors. I'm looking forward to hearing the reports and reviews as these new machines are introduced.