An official from the city of Munich has detailed the biggest challenges facing the city after moving from Windows to Linux.
The German city council spent years migrating more than 15,000 staff to Limux, a custom-version of Ubuntu, and other open-source software - a move the city said had saved it more than €10m ($11m).
"Most people don't really realize that they have Linux and they do not really care," said Jan-Marek Glogowski, a developer in the IT team at the City of Munich told the DebConf Debian developers meeting earlier this month.
"Even when some people were complaining about Linux we were looking at their PCs and there was actually Windows XP running on it," he said of the early days after the move.
"Normal people don't really care" about whether they are using Windows or a Linux-based OS, he said, "they want to do their stuff".
Rather than unhappy users, the biggest challenge faced by the IT team at Munich is keeping the Ubuntu-based OS compatible with new hardware.
Glogowski labelled hardware support a "major problem" for the council as the number of PCs using Limux has grown, with about 18,000 machines currently running the OS.
Don't miss the latest: Munich: The journey from Windows to Linux and back again (free PDF)
Limux is based on Ubuntu LTS - a new version of which is released every two years - and in the interim between new releases the council is having to update the OS to support new hardware.
"After half a year the hardware stack which was delivered with the Ubuntu release or any other Linux release is normally too old for new hardware," he said.
"What does that mean? It means you have a backported kernel, a backported DRM, a backported mesa, Xorg, xorg-drivers."
Glogowski also touched on the difficulty of testing updates to Ubuntu delivered via the Hardware Enablement (HWE) Stack.
"Every time you have a new version of the hardware support you have to check it on all the hardware," he said.
That testing is made more tricky by the fact there are 22 IT organisations within Munich City Council, managing about 50 sites across the city.
"That's really a lot of work, and a lot of work that's not done in the central IT but in the distributed IT."
He said it was "normal" for problems with the updates to appear on hardware managed by these smaller IT outfits that didn't crop up in central IT testing.
In future Munich hopes to move to what he described as "hardware-specific HWE" so "just new hardware has to be tested".
The city's other ambition is to reduce the time it takes to release new versions of Limux. Glogowski said it had taken more than two and a half years to release Limux 5.0, which is based on Ubuntu 12.04 LTS.
"We started on 12.04 in 2012, we had [to wait] for the first point release because there were so many bugs," he said.
It then became necessary to resolve "shortcomings" in LibreOffice 4.1.2 and deal with issues around KDE 4 being "broken" and "mail merge being broken and slow", according to Glogowski.
"It's a really, really long development cycle and we want to cut that down. I hope we will get faster with the next release," he said.
The next major upgrade of Limux will be version 6.0, which will be based on Ubuntu 18.04 LTS, KDE 5 and systemd.
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Nick Heath is chief reporter for TechRepublic. He writes about the technology that IT decision makers need to know about, and the latest happenings in the European tech scene.