14 DAY TRIAL // Recently, Redmond-based software giant Microsoft responded to a series of reports around the Internet regarding a limitation of only 15 applications that could use push notification on the company's new Windows Phone 7 operating system. Indeed, the limitation is there, but it was put in place only for third-party applications which would like to use push notifications and/or live tiles, and not for Microsoft's own software solutions as well.
Basically, this means that one would be able to have more than 15 live tiles on a Windows Phone 7 device, provided that he / she installs a number of 15 third-party applications that use this feature, in addition to those provided by Microsoft.
At the moment, there is no API that would enable the listing of applications using push notifications, but users would be informed on reaching the limit of 15 installed such apps.
However, it appears that only applications which have the push notification or tiles push enabled would be taken into consideration here. Moreover, those apps which use only scheduled tiles updates are not counted towards the limit either.
Each such application is subscribed to a channel. However, one would not have to uninstall the app to free a channel, as that might be done through simply unsubscribing the software solution from the push notification feature.
Here's what a recent post from Microsoft's Jaime Rodriguez states on the matter:
Yes, the limit is fifteen third party applications can be concurrently subscribed to receive push notifications (whether that is a live tile or toast). Parsing it out, the applications that come out of the box (like outlook, people hub, etc.) will not count towards this limit. So there is no limit on 15 live tiles. You can have 20+ if you add it up (that is about 2.5 screens worth of tiles on star menu)
You should not have to go uninstall an application in order to free a slot. If an application is coded well, it should be prompting users and giving them the option on whether they want to use push notifications and/or live tiles (since there is potential bandwidth charges from the operator when these are pushed). If the user never agrees or it unchecks the box to subscribe, the application should free the channel; therefore uninstall should not be required.
If an application subscribes for tile updates, and is never pinned it unfortunately does count. Again, we count the channels.
He also notes that, while the first Windows Phone 7 release comes with the limitation set at 15, future updates might increase the number. However, nothing was announced officially, nor is it certain at this moment.
As for why the limit was there in the first place, Jaime Rodriguez states the following:
The usual thrive to ensure there is a great user experience, good battery life, quality of service on back-end and front-end, bandwidth (cost) , etc. Limit will increase as we get right data on how people use push, impact, etc.
Kevin’s feedback on there not being an API to enumerate all push apps is still valid. I know the product team has heard it (from Kevin, me and others) so I hope that gets addressed or the limits go high enough that the problem becomes a moot point.