Accession is currently supported on four platforms: Android and iOS (for Mobile), and Windows and OSX (for Desktop). New updates for software and the OS are periodically made available to end-users, and when the end users upgrade is under their control. Occasionally new OS releases or software updates result in poor behavior of existing Accession clients.

When Metaswitch becomes aware of a new OS or software release, we will update this article to explain the current level of support of Accession clients for that release. We will include the following information.

  • Notice of the new OS release, and when it is expected
  • The expected level of support for Accession clients
    • Full support - fully tested and no know issues
    • Beta support - some testing done, but there may be bugs in some areas
    • Known issues
  • If there are known issues, we will
    • include details of the problem and the expected impact
    • explain any action that can be taken to mitigate the impact
    • where possible, provide a plan for when that problem will be addressed in a forthcoming client release.

As and when new problems with OS or software updates are discovered, they will be documented here. Customers are advised to follow this article in order to receive updates as and when they are made.

Accession Communicator for Mobile


Accession Communicator for Mobile is supported on Android versions from 4 onwards.

Earlier versions of Accesison Mobile (up to V2.15) were supported on Android versions from 2.3.3 onwards, but from V2.16 the minimum supported Android version is 4.

Google Play OpenSSL warning

April 2016: Some customers have received an email from Google warning of a vulnerability in the OpenSSL library used by Accession, along with a warning that the OpenSSL library must be upgraded before July to allow the app to be uploaded to the app store. Accession's use of this library means it isnot exposed to the vulnerability, so existing apps remain secure. We will release a patch in V2.16 to upgrade the OpenSSL library used by Accession so that it does not trigger the warning from Google.

Android N

March 2016: The next Android OS update (N) is available for early developer preview, but is not expected to be released for several months yet. As Android N is not released, it is not currently supported by Accession. We will provide a further update nearer to the official release.

Android M (Marshmallow)

September 2015: clients running Accession V2.13 or lower may not receive incoming calls after upgrade to Android M (Marshmallow)

Issue: Android M contains a new power-saving feature whereby apps may be put into standby if the phone has not been interacted with for some time (e.g. when left on a desk). If Accession is put into standby, its registration will expire and so it will be unable to receive Accession calls.

Workaround: Users can work around the issue by putting Accession on the list of apps that are never put on standby. This can be done via the Android settings menu.

Upgrade plan: Users should upgrade to Accession V2.15.


Accession Communicator for Mobile is supported on iOS versions from 7 onwards.

Earlier versions of Accession Mobile (up to V2.15) were supported on iOS versions from 5 onwards, but from V2.16 the minimum supported iOS version is 7.

iOS 9

September 2015: iOS 9 is fully supported for all Accession versions, with the exception of the new iPad Pro which has not yet been tested.

Accession Communicator for Desktop


Accession Communicator for Desktop is currently fully supported on Windows 7, 8, 8.1 (Desktop edition) and 10.

Windows 10

Accession Desktop is fully supported on Windows 10. This applies to all Accession Desktop clients running V2.18 or higher.

May 2016: 'sip', 'tel' and 'callto' URIs may not work with Accession on Windows 10.

Issue: The method used by Windows for apps to register as URI handlers is changed in Windows 10. As a result, Accession will not automatically handle 'sip', 'tel' and 'callto' URIs when running on Windows 10. Additionally, Accession will not appear in the new Windows 'Default programs' dialog that appears when a 'sip', 'tel' or 'callto' URI link is clicked.

Workaround: There is no known workaround at present.

Upgrade plan: This issue is fixed in the V2.21 release of Accession Desktop, expected in July 2016. Users should upgrade to this release when it is available.

Outlook 2016

November 2015: Accession Desktop is incompatible with Outlook 2016. Running both together results in an Outlook crash. (All previous versions of Outlook are supported, from Outlook 2007. This includes running with Office 365.)

Issue: Accession Desktop is currently not compatible with Outlook 2016. Running Accession will cause Outlook 2016 to crash. This affects all current Accession versions before V2.18.09 and V2.19.05.

Upgrade plan: Updated 1st February 2016: This issue is fixed in Accession Communicator for Desktop release V2.18.09+ or V2.19.05+. We recommend all customers upgrade to in order to work correctly with Outlook 2016.


Accession Communicator for Desktop is currently supported on Mac OSX versions running OSX 10.7 or higher.

November 2015: this includes the latest El Capitan release (OS X 10.11).

There are no known new release restrictions on Mac.