Changes in operation from Raspbian to Raspios

[PeterM7]

File: /en/202306/use-mqtt-with-raspberry-pi.md

I used to have my system working on a Raspberry Pi using Raspbian Buster, but since the 'upgrade' to Raspios, I cannot make it work. I think that it is because Raspios uses Systemd.
My subscriber file is /home/peterm/pi/mqtt/subscriber.py [ changed with Raspios from /home/pi/mqtt... ]
and I think that I need a file in /lib/systemd/system/ called subscriber.service that calls subscriber.py, but I cannot find a reliable way of configuring this file.

I would appreciate any advice that you can give me on this.

PeterM.

[Adek06]

Hi Peter,

To help you effectively, could you please provide a few more details?

1. What exactly isn’t working after the upgrade?
   For example, is the script not starting on boot, not running at all, or throwing an error?

2. Have you already created a subscriber.service file?
   If so, please share the contents of that file so I can check for any issues.

3. How are you trying to run or enable the service?
   Are you using commands like systemctl start subscriber.service or systemctl enable subscriber.service? Let me know what you've tried and what the output is.

4. Any error messages or logs?
   If you’ve seen any error messages (from the terminal or in the system logs using journalctl -u subscriber.service), please share them.

Once I have this information, I’ll be in a much better position to guide you.

[PeterM7]

1. I cannot see any evidence that the Wemos publisher is making contact with the subscriber over the Wifi. The R-Pi is configured as an Access Point also so that it is independent of my home network. That also has its own limitations on seeing what is happening.

2. I do not know what information to put in the subscriber.service file. In my notes I cannot find anything about that. [I am returning to this after some time away]. I have just checked the SD card and I don't have this file. This is where I am stopped.

My poor notes on what I do:
https://madsmaddad.blogspot.com/2024/05/lets-get-car-4-working-again-may-2024.html

[PeterM7]

It's possible that my answer is here: It was my question 5 years ago!
https://forums.raspberrypi.com/viewtopic.php?t=289311

Will try this later and see where I get to.

[PeterM7]

Progress.

1. Installing networking on RaspIOS as an Access Point, but the help that you find on this does not tell you that you also have to install dnsmasq to set up DHCP. resolved.
2. Found the config to set up subscriber.service. [Allowed Mosquitto as not needing security password for testing]
   "
   [Unit]
   Description=MQTT Subscription Service
   After=multi-user.target

[Service]
Type=idle
ExecStart=/usr/bin/python3 /home/pi/mqtt/subscription.py

[Install]
WantedBy=multi-user.target
"
Note that with RaspIOS you have a user name, so the path became: /home/peterm/pi/mqtt/subscription.py and I removed the 'pi' folder for simplicity.

In my subscriber.py file I had a call to a test file for debug output. Yes, I had to change that path too.

Current state: Subscriber status:
"
× subscriber.service - MQTT Subscription Service
Loaded: loaded (/lib/systemd/system/subscriber.service; enabled; preset: enabled)
Active: failed (Result: exit-code) since Sun 2025-06-29 16:00:21 BST; 6s ago
Duration: 2.839s
Process: 1004 ExecStart=/usr/bin/python3 /home/peterm/mqtt/subscriber.py (code=exited, status=1/FAILURE)
Main PID: 1004 (code=exited, status=1/FAILURE)
CPU: 2.604s

Jun 29 16:00:20 raspberrypi python3[1004]: import RPi.GPIO as GPIO
Jun 29 16:00:20 raspberrypi python3[1004]: File "/usr/lib/python3/dist-packages/RPi/GPIO/init.py", line 927, in
Jun 29 16:00:20 raspberrypi python3[1004]: RPI_INFO = _get_rpi_info()
Jun 29 16:00:20 raspberrypi python3[1004]: ^^^^^^^^^^^^^^^
Jun 29 16:00:20 raspberrypi python3[1004]: File "/usr/lib/python3/dist-packages/RPi/GPIO/init.py", line 428, in _get_rpi_info
Jun 29 16:00:20 raspberrypi python3[1004]: raise NotImplementedError(
Jun 29 16:00:20 raspberrypi python3[1004]: NotImplementedError: This module does not understand old-style revision codes
Jun 29 16:00:21 raspberrypi systemd[1]: subscriber.service: Main process exited, code=exited, status=1/FAILURE
Jun 29 16:00:21 raspberrypi systemd[1]: subscriber.service: Failed with result 'exit-code'.
Jun 29 16:00:21 raspberrypi systemd[1]: subscriber.service: Consumed 2.604s CPU time.
~
"

Here is another change then, that is catching me. "This module does not understand old-style revision codes"
I think I need help here.
Thanks.

[PeterM7]

Adek, more information. I am still stuck.

To help you effectively, could you please provide a few more details? 1. What exactly isn’t working after the upgrade? For example, is the script not starting on boot, not running at all, or throwing an error Error:

subscriber.service - MQTT Subscription Service Loaded: loaded (/lib/systemd/system/subscriber.service; enabled; preset: enabled) Active: failed (Result: exit-code) since Sun 2025-06-29 16:00:21 BST; 6s ago Duration: 2.839s Process: 1004 ExecStart=/usr/bin/python3 /home/peterm/mqtt/subscriber.py (code=exited, status=1/FAILURE) Main PID: 1004 (code=exited, status=1/FAILURE) CPU: 2.604s Jun 29 16:00:20 raspberrypi python3[1004]: import RPi.GPIO as GPIO Jun 29 16:00:20 raspberrypi python3[1004]: File "/usr/lib/python3/dist-packages/RPi/GPIO/__init__.py", line 927, in <module> Jun 29 16:00:20 raspberrypi python3[1004]: RPI_INFO = _get_rpi_info() Jun 29 16:00:20 raspberrypi python3[1004]: ^^^^^^^^^^^^^^^ Jun 29 16:00:20 raspberrypi python3[1004]: File "/usr/lib/python3/dist-packages/RPi/GPIO/__init__.py", line 428, in _get_rpi_info Jun 29 16:00:20 raspberrypi python3[1004]: raise NotImplementedError( Jun 29 16:00:20 raspberrypi python3[1004]: NotImplementedError: This module does not understand old-style revision codes Jun 29 16:00:21 raspberrypi systemd[1]: subscriber.service: Main process exited, code=exited, status=1/FAILURE Jun 29 16:00:21 raspberrypi systemd[1]: subscriber.service: Failed with result 'exit-code'. Jun 29 16:00:21 raspberrypi systemd[1]: subscriber.service: Consumed 2.604s CPU time. ~

1. Have you already created a subscriber.service file? If so, please share the contents of that file so I can check for any issues. [Unit]

Description=MQTT Subscription Service After=multi-user.target [Service] Type=idle ExecStart=/usr/bin/python3 /home/peterm/mqtt/subscriber.py [Install] WantedBy=multi-user.target

1. How are you trying to run or enable the service? Are you using commands like systemctl start subscriber.service or systemctl enable subscriber.service? Let me know what you've tried and what the output is. This is what I used and on reboot I got the message above. 1. 2. Any error messages or logs? If you’ve seen any error messages (from the terminal or in the system logs using journalctl -u subscriber.service), please share them. Error message is above.

cat /proc/cpuinfo gives HArdware: BCM2835 Revision : 000f Model : B rev.2 This is the old unit that I use on my testbed. I note that the revision should be a 32 bit code, not this 16 bit one, and I don't know where to go to change it, if I can. When I have the software working I may be using a Pi-zero on the Rc car. This is required for testing because it has an Ethernet port.

1. Once I have this information, I’ll be in a much better position to guide you.

Thanks for any guidance. Peter M.

[Adek06]

Hi Peter,

Thanks for the detailed info — that really helps.

From the error:

NotImplementedError: This module does not understand old-style revision codes

and your /proc/cpuinfo output showing:

Revision : 000f
Model : B Rev.2

…it looks like you're running this on an early Raspberry Pi model with a 16-bit revision code. Recent versions of the RPi.GPIO library seem to have dropped support for these older codes, which is why the script is failing during import.

I don't have this particular Pi model on hand, so I can't test it directly — but based on the error and the board revision, it's likely a compatibility issue between the hardware and the GPIO library version.

You could try uninstalling the current version of RPi.GPIO and installing an older one that still supports legacy revisions. I’ll need to check which specific version last supported these older models, but something before the latest releases should work.

As a starting point, try this:

sudo apt remove python3-rpi.gpio
sudo pip3 install RPi.GPIO==0.7.0  # try this, but I’ll confirm later

Then test the script manually:

python3 /home/peterm/mqtt/subscriber.py

If it runs without the same error, you can restart your systemd service:

sudo systemctl restart subscriber.service

Once I’ve had a chance to look into which version officially supports the old-style revision codes, I’ll follow up with a more definitive answer.

[PeterM7]

Current state, Cannot find python3-rpi.gpio to remove or any variation on that such as without python3, and using RPi.GPIO. Trying the install it wants me to create a virtual environment, which I am reluctant to do without knowing more. Thinking about how to find rpi.GPIO, and how to install the old version without a VENV. Peter

…

On Thu, 10 Jul 2025 at 14:56, Adek You ***@***.***> wrote: *Adek06* left a comment (emqx/blog#1551) <#1551 (comment)> Hi Peter, Thanks for the detailed info — that really helps. From the error: NotImplementedError: This module does not understand old-style revision codes and your /proc/cpuinfo output showing: Revision : 000f Model : B Rev.2 …it looks like you're running this on an early Raspberry Pi model with a 16-bit revision code. Recent versions of the RPi.GPIO library seem to have dropped support for these older codes, which is why the script is failing during import. I don't have this particular Pi model on hand, so I can't test it directly — but based on the error and the board revision, it's likely a compatibility issue between the hardware and the GPIO library version. You could try uninstalling the current version of RPi.GPIO and installing an older one that still supports legacy revisions. I’ll need to check which specific version last supported these older models, but something before the latest releases should work. As a starting point, try this: sudo apt remove python3-rpi.gpio sudo pip3 install RPi.GPIO==0.7.0 # try this, but I’ll confirm later Then test the script manually: python3 /home/peterm/mqtt/subscriber.py If it runs without the same error, you can restart your systemd service: sudo systemctl restart subscriber.service Once I’ve had a chance to look into which version officially supports the old-style revision codes, I’ll follow up with a more definitive answer. — Reply to this email directly, view it on GitHub <#1551 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AP7SSHJQWTKDHEQDDTOMH2T3HZWHLAVCNFSM6AAAAACAD7GZLCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTANJXGU3DOOJTGI> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[PeterM7]

Progress. I removed the line import RPi.GPIO as GPIO from the subscriber.py file, and now I do not have that error. I just have to sort out the new error that I have: ***@***.***:~ $ sudo systemctl status subscriber × subscriber.service - MQTT Subscription Service Loaded: loaded (/lib/systemd/system/subscriber.service; enabled; preset: enabled) Active: failed (Result: exit-code) since Wed 2025-07-16 21:12:58 BST; 3min 55s ago Duration: 1d 19h 12min 10.815s Main PID: 375 (code=exited, status=1/FAILURE) CPU: 2.463s Jul 16 21:12:57 raspberrypi python3[375]: return socket.create_connection(addr, timeout=self._> Jul 16 21:12:57 raspberrypi python3[375]: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^> Jul 16 21:12:57 raspberrypi python3[375]: File "/usr/lib/python3.11/socket.py", line 851, in cre> Jul 16 21:12:57 raspberrypi python3[375]: raise exceptions[0] Jul 16 21:12:57 raspberrypi python3[375]: File "/usr/lib/python3.11/socket.py", line 836, in cre> Jul 16 21:12:57 raspberrypi python3[375]: sock.connect(sa) Jul 16 21:12:57 raspberrypi python3[375]: TimeoutError: timed out Jul 16 21:12:58 raspberrypi systemd[1]: subscriber.service: Main process exited, code=exited, stat> Jul 16 21:12:58 raspberrypi systemd[1]: subscriber.service: Failed with result 'exit-code'. Jul 16 21:12:58 raspberrypi systemd[1]: subscriber.service: Consumed 2.463s CPU time. Thanks for your help and advice. This site was helpful: https://raspberrytips.com/gpio-zero-guide-raspberry-pi/ Cheers, Peter M.

…

On Thu, 10 Jul 2025 at 14:56, Adek You ***@***.***> wrote: > *Adek06* left a comment (emqx/blog#1551) > <#1551 (comment)> > > Hi Peter, > > Thanks for the detailed info — that really helps. > > From the error: > > NotImplementedError: This module does not understand old-style revision > codes > > and your /proc/cpuinfo output showing: > > Revision : 000f > Model : B Rev.2 > > …it looks like you're running this on an early Raspberry Pi model with a > 16-bit revision code. Recent versions of the RPi.GPIO library seem to have > dropped support for these older codes, which is why the script is failing > during import. > > I don't have this particular Pi model on hand, so I can't test it > directly — but based on the error and the board revision, it's likely a > compatibility issue between the hardware and the GPIO library version. > > You could try uninstalling the current version of RPi.GPIO and installing > an older one that still supports legacy revisions. I’ll need to check which > specific version last supported these older models, but something before > the latest releases should work. > > As a starting point, try this: > > sudo apt remove python3-rpi.gpio > sudo pip3 install RPi.GPIO==0.7.0 # try this, but I’ll confirm later > > Then test the script manually: > > python3 /home/peterm/mqtt/subscriber.py > > If it runs without the same error, you can restart your systemd service: > > sudo systemctl restart subscriber.service > > Once I’ve had a chance to look into which version officially supports the > old-style revision codes, I’ll follow up with a more definitive answer. > > — > Reply to this email directly, view it on GitHub > <#1551 (comment)>, or > unsubscribe > <https://github.com/notifications/unsubscribe-auth/AP7SSHJQWTKDHEQDDTOMH2T3HZWHLAVCNFSM6AAAAACAD7GZLCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTANJXGU3DOOJTGI> > . > You are receiving this because you authored the thread.Message ID: > ***@***.***> >