Problems with Telekom fixed network? This could be the reason

An update in the Telekom network means that Fritzboxes with old firmware no longer function properly. Customers must therefore take action.

Many Telekom customers use a Fritzbox as a router. However, they should definitely check the installed firmware now. If it is an old version, the Fritzbox can no longer be used properly. Among other things, telephony via the fixed network is no longer possible. But what is the reason for this and what can Telekom customers do? atechbook explains.

Update in the Telekom network impairs function of older Fritzboxes

Deutsche Telekom updated its network on March 15 to improve security standards, among other things. However, AVM still uses the Real-Time Transport Protocol (RTP) for IP-based telephony in Fritz!OS 7.25. Here, the media stream is transmitted unencrypted, which is not permitted according to Telekom’s security standards.¬†As a result, customers whose Fritzboxes run Fritz!OS 7.25 can no longer make calls in Telekom’s fixed network. Internet use is not affected, however, and is still possible without restrictions.

According to the network operator, the problem only affects the firmware mentioned. Owners of a Fritzbox therefore have two options to react to the update in the network. They can either update their Fritzbox to version 7.29, or – if the latest software is not available – downgrade to a previous Fritz!OS version 7.25. A list of previous Fritz!OS versions for different Fritzboxes can be found here. However, this step is not really recommended, as it removes many innovations and system optimizations from the Fritzboxes that AVM rolled out for better operation.

Which Fritzboxes are affected?

AVM released the Fritz!OS 7.29 in November 2021. Since then, many Fritzboxes have received the update. However, there are still a few models for which the Fritz!OS is not available. These are mainly older Fritzboxes like the 7390, the 7360 or the Fritzbox 7272. However, these routers usually run a much older firmware version anyway, which makes a downgrade unnecessary.

Restrictions caused by the Telekom network update will therefore be noticed primarily by those customers who have not activated the automatic updates on their router and thus may not have installed the latest Fritz!OS version. It is therefore advisable to check the firmware version on the Fritzbox interface. To do this, go to and log in with your data. On the top right of the start page, you will see the firmware currently installed on the Fritzbox. However, you can also search for a newer version under “System” and “Update” and download and install it right there.


  • Telekom announcement