HTC and their lackluster business politics regarding the hardware accelerated graphics chips slumbering inside the whole lineup of last generation devices drove me away from their name quite quickly. I do own a HTC again, but it's Android powered and there was no real competition to chose from when I bought it. But as I let HTC go I can and most likely will if forced to (sounds soooo endlessly stupid) leave any other brand, Nokia included. In fact I never ever touched a Nokia again after the desaster they pulled off with the Nokia 6000. And it's only for the N900 I'll have a look at them again, now come on guys, don't screw this up again

So... Qt 4.6 is now in Maemo 5 extras-devel. It's alpha-ish but already pretty decent according to the first developers trying it out.

The Harmattan application framework is based in Qt 4.6. Plain Qt applications running in this Maemo 5 Qt 4.6 port should also run on Maemo 6 (perhaps with recompile, perhaps with little polishing tweaks... who knows at this point).

This also defines the minimum expectation: plain Qt apps for Maemo 6 can run on Maemo 5 with little or no tweaking.

Now think of the Web Runtime apps that will be running on top of Webkit on top of Qt 4.6.

Qt 4.6 is being designed with the focus on compatibility across Maemo, Symbian, Windows Mobile and other platforms shipping it (Moblin? Ubuntu? etc). Now compare that to the jump from Maemo 5 to Maemo 6. It's still the same platform.

Qt compatibility is nice, but I don't think the basic concern here is lack of backporting. I could just as well tweak Qt 4.6 to run on Diablo, but that will not fix metalayer-crawler or some other system level component's problems. The question is if with Harmattan we'll see the fixed-in-fremantle-which-you-cannot-upgrade-to story again and how Mer (and it's readiness for the general public) fits the picture when Harmattan device(s) hit the streets.

Just a comment about running a plain Qt app on Maemo 6. Maemo 6 is fully QGraphicsView based application framework, so plain Qt apps based on QWidget will not (probably) look nice. Though they can be compiled and run on Maemo 6.

I hope they will provide like "MaemoStyle" for plain Qt apps and Hildon like port where e.g. all the Qt menus (file, edit, etc..) are handled by the application framework as the Qt 4.6 for Maemo 5 does.

So basically if you want to look at to the future, implement your application based on QGraphicsView and then it should run on Maemo 5 and Maemo 6 platforms with less effort needed later. On the otherhand, the Maemo 6 UI framework will provide bunch of QGraphicsWidget based widgets so it might be quite difficult to find a silver bullet that makes your application fit perfectly on Maemo 5 & 6. You can alway take a look at the Maemo 6 UI framework source code from gitourious and see how things work or will work unless they decide to change some essential parts.

Another thing that came to my mind is that, depending on which Qt 4.6 version is ported to Maemo there might be some differences. For example how well Qt's gesture API will be supported in official Maemo 5 version? I tested to build a Qt application that was based on "too new" Qt 4.6 version and when I compiled the app to Maemo 5 I noticed that QGesture and QTouchEvent were not included that version. Of course the version can always be updated later.

I might be wrong here also so please correct me if I have understood somethig wrong.

We make the earliest releases of Qt 4.6 for Maemo 5, the Maemo 6 UI Framework and Maemo 6 Qt (to come with a first Harmattan pre-release, just like we had Fremantle pre-releases) precisely to have time for everybody to test, give feedback, fine tune & so on.

Title says it all:

I'd like to know if there are any estimates for the release date of Maemo6, and if it will run on the N900. And if so would it maybe b pushed as an update ?

I'm thinking in terms of the long run, if it's worth it to buy the N900..

thank you

Ad 1st no release date (mmh the maemo5 device is just shipping and you ask for the next gen?!)
Ad 2nd not so far (but keep asking maybe it becomes yes)
Ad 3rd yes (keep in mind that Qt programs most likely will run on all three symbian maemo5 and maemo6)

Hah, N900 isn't even released, so, who can say. Hopefully Nokia will announce a realistic delivery date for Maemo6, but that's years in the future. 2016

Will n900 run Maemo 6? My understanding is that no, there will be serious hardware changes so it won't.

As for when it will be released: best estimates say 12-18 months after maemo 5. Then add a month or two for delays in delivery and shipping... Somewhere around spring/summer 2011?

Personally, I'm reckoning that the n900 will be good for two or three years (about the life of a phone). If maemo 6 is coming on a device that's physically very different (or a range of devices) it may or may not be what I want.

there are already several threads on that topic (search is your friend):
here's one
here's another

all the answers are there
to sum it up in one sentence: it's not officially decided yet, but it's unlikely to happen.