Regarding FM onm the Xperia :
currently Sailfish 2.2.0 doesn't have a functionnal driver, according to Jolla's announcements.
(There's no /dev/...blah... showing up to play radio with).

Maybe they'll manage to activate the functionality in a future kernel.

If you absolutely rely on radio musique, but can at least get a good connection ( either Wifi or 3G/4G), consider using web radios in the meantime.

Sailfish is, in my opinion, a good solution if you don't mind getting your hands dirty and hack and tweak stuff here and there.
While at the same time you still have some access to Android and don't miss the applications that you might be needing.

Beware, the current Android compatibility has very little direct hardware access. e.g.: It can't directly drive Bluetooth devices.
So forget using an Android app that talks directly to your sport health monitor gadget.
Sailfish has some bluetooth support, so it can handle some devices (e.g.: Bluetooth speakers), which will then show as generic audio output to the android apps. You can thus still listen to musique with Spotify on your bluetooth speakers.

By the time of Sailfish 3.0, Jolla might be considering some better solution, but aren't allowed to speak about it yet.

we could definately do with an update from Jolla on where things stand.

re: obligatory plug for XA2 Plus support - if there is no FM support in Sailfish, then it will sting less in a phone iwith no 3.5mm...

This might even save me money. Many budget wireless carriers don't explicitly support tethering, and those that do typically charge extra. If there's no way to detect a host computer (short of some heuristic test), then I could potentially change carriers or rework my bill.

Just thought of another question. Does Sailfish have any problem connecting to Ad-Hoc networks? (I know Kindle devices do.) I'll probably use JoikuSpot on my Symbian phone for a while until I'm ready to install a SIM in the Xperia.

Yup, you definitely DO NOT need the "tethering" option from you carrier.

Indeed, on the ISP point of view all traffic is generated from smartphone. (Some time this happens to be due to a local app, some time "on the behalf of" another device that the smartphone routes. But there's only 1 single IP address ever seen, the routing handles masquerading)

Ad-Hoc : haven't tested with the Xperia X specifically.
But, back with my Jolla 1 I was in the same situation (was tethering from my HP Pre3 until I switched SIMs around), so the OS it self supports it.
Unless there's a weird bug on the Wifi chip on the Xperia X that I'm unaware of, it should work as expected.

jTox is in heavy development to get work audio/video. owner told.
kaidan will come to sailfish o.s when QT5.9 hit s.f. same.

When my brother-in-law was running small ISP, we routinely checked TTL of packets and applied fingerprinting when in doubt. The question is, does the ISP even bother to check.

(and there was this guy, who tried to use WinXP connection sharing and misconfigured it. As the radio network had some delays, his DHCP was "closer" to nearly half of the nodes, so he became their gateway. He ate his traffic quota in no time ;P )

The bold links in post #1 are dead.
Is there any official roadmap?
I can see the jolla blog and some other more promotional stuff on their sites, but not an actual roadmap/development status...

Given that the above was posted in May 2015, is there any news? It would be lovely to have Miracast on my Sailfish device.

(I am aware of Screencast and Jupii, both of which are a nice proof of concept and fun to play with for half an hour but unusable for any practical purposes and completely unusable for the intended purpose.)

if jolla are sensible they'll announce xperia 10 II support at least a month prior to amazon prime day or black friday (whichever comes first).

everyone knows sony prices high for midrange specs, a sale price of sony hardware will drive sfos sales.

time for a roadmap blog post...