iOS13 connection problems

Since the iOS13 release, connection problems between iPhone/iPad and the Truma iNet Box occur. In the meantime, we have been able to identify two different issues – but have not yet been able to solve the problems, even in cooperation with Apple support.

Here you can find a detailed error description and technical information about the causes of the problems. As soon as we have new findings, we will keep you up to date in the Truma service blog and in the App News.

Have you had experiences that you would like to share with other users and us? Then use the comment function in our service blog! We look forward to exchanging ideas with you.

iPhone 6s to iPhone XR (iOS13) / iPads (iPadOS13) – Connection problems

Error Picture

After three days at the latest, a Bluetooth connection to the Truma iNet Box can no longer be established. The blue LED lights up constantly, even without an active connection. Control is therefore no longer possible in the near field. In the far field, no LevelControl values can be called up via SMS. The error only occurs sporadically.

Background knowledge

Each Bluetooth LE device has 40 Bluetooth channels, three of them are used as advertising channels. These are used to establish a connection between Bluetooth devices. To do this, the Bluetooth LE device sends short attentional messages via advertising signal on at least one of the three advertising channels. The device then waits for a connection request from another Bluetooth device. When the connection request is made, the devices switch to one of the remaining 37 channels to receive a larger block of data from the device.

Technical cause

Devices with iOS13 version send a constant advertising signal via Bluetooth. Even if the connection is already established, the app is active in background mode, is completely terminated or even uninstalled.

If no app is active while the Truma iNet Box is trying to establish the connection, the connection will fail. What otherwise works within a few seconds, is then resource-intensive for the Truma iNet Box, interferes with other connections or prevents the establishment of further connections with active Truma Apps (e.g. Truma LevelControl values are displayed with a long delay).

If the Truma app queries whether the advertising signal is being sent, it is informed that this is not the case. Although the functions provided by Apple in the interface have not changed with iOS13, they no longer work as desired since the update.


Restarting the Truma iNet Box will result in an improvement until the situation recurs. The best way to restart the Truma iNet Box is to disconnect it from the power supply.


Why do other Bluetooth devices work with iOS13, but not the Truma iNetBox?

The Truma iNetBox uses the iOS devices as “peripherals” and does so with one of the first Bluetooth protocol versions to support this. Although this configuration is very common, it is obviously not the focus of Apple’s test coverage.

Why was the problem not resolved during the beta phase of the iOS 13 updates?

The issue was revealed with the first iOS13 beta, but it quickly became clear that we were dependent on Apple to fix it. At the same time, we received a lot of feedback regarding misbehavior in other Bluetooth applications. Apple has now fixed most of the bugs – but unfortunately not the one concerning the Truma iNet Box.

What is being done to remedy the malfunction?

We are working hard to eliminate the malfunction together with Apple. In addition, we are also trying to influence Apple via the manufacturer of our Bluetooth chip and at least, work out a workaround.

What can I do if the error occurs?

The error occurs, if there are several iOS devices in the vicinity of the Truma iNet Box that have the Truma app installed but the app is not active.

You can do this:

1) Exit Truma App

2) Turn Bluetooth off and on again (in the settings and not via shortcut menu).

This temporarily stops the unwanted sending of the advertising signal and makes it easier for the Truma iNet Box to establish a connection with other iOS devices.

iPhone 11 – Connection problems

Error picture

It is not possible to establish a new Bluetooth connection to the Truma iNet Box. The malfunction always occurs.

Background information

The connection between the Truma iNetBox and an iOS device is encrypted for security reasons.  To this end, various keys are generated when the Truma iNetBox is set up, one of which is stored on the Truma iNet Box. This guarantees that a secure connection can be established immediately after the Truma iNet Box is set up.

Technical cause

Once the connection is re-established, the iPhone 11 does not respond to the encryption request and stops communicating with the Truma iNet Box. The problem occurs even though all Bluetooth specifications have been implemented correctly. The reason for this is a modified chipset that Apple uses in the iPhone 11 and is therefore not compatible with the Truma iNet Box.


A workaround is currently not possible. A factory reset of the Truma iNet Box only enables a one-time connection via Bluetooth, for example to set up Truma LevelControl and GSM.


Why does only the iPhone 11 not work with the Truma iNet Box?

Apple uses a different chipset in the iPhone 11 than in the previous models. Although all Bluetooth devices must undergo conformity tests, this chipset is not compatible with the Truma iNetBox.

Why don’t we just do without encryption?

Apple uses another security mechanism that does not work without encryption. An unencrypted connection would break off as soon as the iOS device randomly changes the Bluetooth address.

What can I do if the error occurs?

The error always occurs and there is currently no workaround. Only a factory reset of the Truma iNet Box, in which the Bluetooth button is pressed for 20 seconds, allows a one-time connection.

30 thoughts on “iOS13 connection problems

  1. -Update 06.05.2020-

    Hello, everyone,
    as promised, the status update:
    -What’s the current status?
    Good news!, the internal and field test was successfully completed. There were no problems, the function via iPhone 11 and SE is 100% given.

    -When will be released?
    We have uploaded the builds and they are currently being tested by Apple and Google. As soon as this is completed we will release the update immediately.

    -What will be released?
    The new update includes a new app version and the corresponding firmware for the iNetBox.
    Both components are required for full functionality.

    -How will I be informed?
    As usual, we will publish a message via App-News parallel to the app

    -Must I pay attention to something or how do I get the new firmware on my iNet box if the connection is not stable?

    Especially users of firmware 2.4.0 are affected, as it is much more unstable than its successor 2.5.0.

    The following procedure has proven to be successful:
    – Delete the Bluetooth connection on the iPhone first (iNet Box – “Ignore this device”)
    – Then reset the Truma iNet Box to its factory settings. To do this, press the Bluetooth button on the iNet box for 20 seconds. This resets all settings.
    – Finally, reconnect the iPhone (11 or SE) and the Truma iNet box using the Truma app and carry out the update immediately afterwards.

    Ludwig Schmid
    -Service Center-

  2. -Interim status, update 31.05.2020-

    Hello, everyone,
    first of all I would like to thank you for all the feedback and commitment, no matter how you did it.
    My statement that the fix release for the iPhone 11 problem will be in the available at middle/end of May,can no longer be confirmed. We are still in the field test (no bugs appeared until now), as well as in the internal test. Only after this test has been completed successfully, a release is possible.

    The current plan covers the coming week.
    -If there are changes or unexpected problems I will update you here again.

    Ludwig Schmid
    -Service Center-

    PS: Because the iPhone SE 2020 hardware is identical to the iPhone 11, the same symptoms will be also fixed.

  3. Ooops just fitted the inet box then found this thread.
    iphone 11 Pro one time connection allowed me to set up sim card then refused to connect to bluetooth but connection through the sim card seems to carry on working.
    Set up wifes iphone X no problem.
    Are we talking days weeks or months for a fix.

  4. The iPhone 11 connection problem seems also to exist with the new 2020 SE. Presumably same Bluetooth chipset? I can only establish one time connections after a reset.

  5. Just installled the latest iNet update 2.5.0 with my Android smartphone. After the update I unsuccesfully tried to connect to my iPhone X with IOS 13.3.1. Then I did a reset of the iNet box but afterwards I’m still unable to connect to my iPhone X.

    • Hi r3mc0,
      can we check your iPhone X together? I can´t believe it´s not connectable at all.
      Before alle Phones should be able to connect in general, but with interruption after some time.

      Did you even tried to delete the old BT connect from your iphone and generate a new one?

      Ludwig Schmid
      Service Center

  6. Hi

    I can’t update software version. I’m correctly connected but the +update software” is not active. What can I do?

    • Hi Andrea,
      today we uploaded some news about.
      I hope it will give you a feeling.

      “Dear Campers,

      As you probably noticed, we rolled out a new firmware version for the Truma iNet Box just before Christmas. We released the firmware so spontaneously to at least reduce the iOS13 connection problem so that it occurs less often during your Christmas holiday period. In certain circumstances, version 2.4.2 will alleviate the reconnection problem for iOS13. However, it has no effect on the iPhone 11 connection problem.

      Firmware 2.4.3 on the starting blocks

      In the meantime, we have made progress: The upcoming firmware 2.4.3 will resolve the problem for all older iOS13-compatible devices, including the iPhone X-family. This firmware is currently undergoing a technical protection process. We will make the firmware available to you as soon as it has successfully passed all the tests.

      iPhone 11 problem in progress at Apple

      Unfortunately, we are not yet able to offer iPhone 11 users a reliable solution for this problem. We reported the issue to Apple some time ago and are being kept up to date on the status via a ticket. The ticket has since been changed to “in progress” and the first in-depth technical discussion took place. Apple have all the information and will now analyse it. As soon as we have any new information, we will update you here. The Service blog is also a good place to keep up to date:

      Finally, we would like to thank you for the excellent discussions on and relating to the Truma Service blog. Your feedback has really helped us to carry out further analysis.

      Kind regards,
      Your Truma team”


      Ludwig Schmid
      Service Center

    • Hi Graham,
      we still working on a solution. Unfortunately we have to ask you for patience.
      Last tests figured out that under iOS 13.3 it´s possible to connect sometimes, so the behaviour changed and was improved by Apple.

      Happy new year


      Ludwig Schmid
      Service Center

  7. Thank you thought is was just me with this problem not much I can do but leave it up to you boys I have invested a lot of money in the instalment of the inept box in several vans so please sort it it’s a fantastic system when it works

    • Hey Keith,
      thank you for your feedback. We are working on the two topics, and the release provided on Fridays was the first part of the solution.

      Wish you a nice x-mas

      Ludwig Schmid
      Service Center

      • What kind of release? New wersion off app? One I have in App Store it’s from four months ago…?

        I’ll keep my fingers crossed for You Boys but this is seriously a big problem especially in winter time!

        • Hi Jerzy,
          thx for your feedback an wishes. Before XMas, we rolled out FW 2.4.2, which included some basic fixes for the BT connection problem. Some further fixes will be included in A new Firmwarerelease, which is currently under test.
          As soon it´s ready to be rolled out you´ll be notified.

          Ludwig Schmid
          Service Center

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