PaperMC error after upgrade to version 26.1.2

kane6681 · 11 May 2026 16:53

Creating a bug report/issue

I have searched the existing open and closed issues

Required Information

DietPi version | cat /boot/dietpi/.version
- G_DIETPI_VERSION_CORE=10
  G_DIETPI_VERSION_SUB=3
  G_DIETPI_VERSION_RC=3
  G_GITBRANCH=‘master’
  G_GITOWNER=‘MichaIng’
  G_LIVE_PATCH_STATUS[0]=‘applied’
  G_LIVE_PATCH_STATUS[1]=‘applied’
  G_LIVE_PATCH_STATUS[2]=‘applied’
Distro version | echo $G_DISTRO_NAME $G_RASPBIAN
- trixie
Kernel version | uname --all
- Linux DietTower 6.12.85+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.85-1 (2026-04-30) x86_64 GNU/Linux
Architecture | dpkg --print-architecture
- amd64
SBC model | echo $G_HW_MODEL_NAME or (EG: RPi3)
- Native PC (x86_64)
Power supply used | (EG: 5V 1A RAVpower)
- standard pc 500w
SD card used | (EG: SanDisk ultra)
- nvme ssd

Additional Information (if applicable)

Software title | (EG: Nextcloud)
- PaperMC
Was the software title installed freshly or updated/migrated?
- updated to version 26.1.2
Can this issue be replicated on a fresh installation of DietPi?
- not tested
  ← If you sent a “dietpi-bugreport”, please paste the ID here →
Bug report ID | echo $G_HW_UUID

Steps to reproduce

update papermc via dietpi-software reinstall 181

systemctl status papermc
○ papermc.service - PaperMC (DietPi)
      Loaded: loaded (/etc/systemd/system/papermc.service; enabled; preset: enabled)
     Drop-In: /etc/systemd/system/papermc.service.d
              └─dietpi-services_edit.conf
      Active: inactive (dead) since Mon 2026-05-11 18:39:48 CEST; 2s ago
    Duration: 4.213s
  Invocation: 2f42b8b6e5214467beacb9a89df9d1e6
        Docs: https://paper.readthedocs.io/
     Process: 2333157 ExecStart=/usr/lib/jvm/temurin-21-jre-amd64/bin/java -mx1373m -jar /opt/papermc/paperclip.jar --nogui --noconsole (code=exited, status=0/SUCCESS)
    Main PID: 2333157 (code=exited, status=0/SUCCESS)
    Mem peak: 374.9M
         CPU: 2.115s
Mai 11 18:39:48 DietTower PaperMC\[2333157\]: at java.base/java.net.URLClassLoader.findClass(Unknown Source)
Mai 11 18:39:48 DietTower PaperMC\[2333157\]: at java.base/java.lang.ClassLoader.loadClass(Unknown Source)
Mai 11 18:39:48 DietTower PaperMC\[2333157\]: at java.base/java.lang.ClassLoader.loadClass(Unknown Source)
Mai 11 18:39:48 DietTower PaperMC\[2333157\]: at java.base/java.lang.Class.forName0(Native Method)
Mai 11 18:39:48 DietTower PaperMC\[2333157\]: at java.base/java.lang.Class.forName(Unknown Source)
Mai 11 18:39:48 DietTower PaperMC\[2333157\]: at java.base/java.lang.Class.forName(Unknown Source)
Mai 11 18:39:48 DietTower PaperMC\[2333157\]: at io.papermc.paperclip.Paperclip.lambda$main$0(Paperclip.java:38)
Mai 11 18:39:48 DietTower PaperMC\[2333157\]: at java.base/java.lang.Thread.run(Unknown Source)
Mai 11 18:39:48 DietTower systemd\[1\]: papermc.service: Deactivated successfully.
Mai 11 18:39:48 DietTower systemd\[1\]: papermc.service: Consumed 2.115s CPU time, 374.9M memory peak.

Expected behaviour

papermc start as normal

Actual behaviour

papermc does not start
- needs java version 25, but only version 21 is installed

Extra details

…

Joulinar · 11 May 2026 17:13

can you share the entire service log

journalctl -u papermc

Jappe · 11 May 2026 22:09

Yes, version 26 requires Java 25 (Getting started | PaperMC Docs)
But I’m not even able to update to version 26:

 Step: Installing PaperMC: Highly optimised Minecraft server with plugins, written in Java

[FAILED] DietPi-Software | Automatic latest PaperMC download URL detection failed.
[FAILED] DietPi-Software | "https://fill-data.papermc.io/v1/objects/da497e12b43e5b61c5df150e4bfd0de0f53043e57d2ac98dd59289ee9da4ad68/paper-1.21.11-127.jar" will be used as fallback, but a newer version might be available.
[FAILED] DietPi-Software | Please report this at: https://github.com/MichaIng/DietPi/issues
[  OK  ] DietPi-Software | cd /tmp/DietPi-Software
[  OK  ] DietPi-Software | curl -sSfL https://fill-data.papermc.io/v1/objects/da497e12b43e5b61c5df150e4bfd0de0f53043e57d2ac98dd59289ee9da4ad68/paper-1.21.11-127.jar -o paper-1.21.11-127.jar
[  OK  ] DietPi-Software | mv paper-1.21.11-127.jar /opt/papermc/paperclip.jar

kane6681 · 12 May 2026 15:56

Mai 12 17:50:42 DietPi systemd[1]: Started papermc.service - PaperMC (DietPi). 
Mai 12 17:50:44 DietPi PaperMC[713]: Starting org.bukkit.craftbukkit.Main 
Mai 12 17:50:44 DietPi PaperMC[713]: Exception in thread "ServerMain" java.lang.UnsupportedClassVersionError: org/bukkit/craftbukkit/Main has been compiled by 
a more recent version of the Java Runtime (class file version 69.0), this version of the Java Runtime only recognizes class file versions up to 65.0 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.lang.ClassLoader.defineClass1(Native Method) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.lang.ClassLoader.defineClass(Unknown Source) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.security.SecureClassLoader.defineClass(Unknown Source) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.net.URLClassLoader.defineClass(Unknown Source) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.net.URLClassLoader$1.run(Unknown Source) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.net.URLClassLoader$1.run(Unknown Source) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.security.AccessController.doPrivileged(Unknown Source) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.net.URLClassLoader.findClass(Unknown Source) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.lang.ClassLoader.loadClass(Unknown Source) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.lang.ClassLoader.loadClass(Unknown Source) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.lang.Class.forName0(Native Method) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.lang.Class.forName(Unknown Source) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.lang.Class.forName(Unknown Source) 
Mai 12 17:50:44 DietPi PaperMC[713]: at io.papermc.paperclip.Paperclip.lambda$main$0(Paperclip.java:38) 
Mai 12 17:50:44 DietPi PaperMC[713]: at java.base/java.lang.Thread.run(Unknown Source) 
Mai 12 17:50:44 DietPi systemd[1]: papermc.service: Deactivated successfully. 
Mai 12 17:50:44 DietPi systemd[1]: papermc.service: Consumed 1.179s CPU time, 433.9M memory peak. 
Mai 12 17:54:56 DietPi systemd[1]: Started papermc.service - PaperMC (DietPi). 
Mai 12 17:54:58 DietPi PaperMC[15039]: Starting org.bukkit.craftbukkit.Main 
Mai 12 17:54:58 DietPi PaperMC[15039]: Exception in thread "ServerMain" java.lang.UnsupportedClassVersionError: org/bukkit/craftbukkit/Main has been compiled b
y a more recent version of the Java Runtime (class file version 69.0), this version of the Java Runtime only recognizes class file versions up to 65.0 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.lang.ClassLoader.defineClass1(Native Method) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.lang.ClassLoader.defineClass(Unknown Source) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.security.SecureClassLoader.defineClass(Unknown Source) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.net.URLClassLoader.defineClass(Unknown Source) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.net.URLClassLoader$1.run(Unknown Source) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.net.URLClassLoader$1.run(Unknown Source) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.security.AccessController.doPrivileged(Unknown Source) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.net.URLClassLoader.findClass(Unknown Source) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.lang.ClassLoader.loadClass(Unknown Source) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.lang.ClassLoader.loadClass(Unknown Source) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.lang.Class.forName0(Native Method) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.lang.Class.forName(Unknown Source) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.lang.Class.forName(Unknown Source) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at io.papermc.paperclip.Paperclip.lambda$main$0(Paperclip.java:38) 
Mai 12 17:54:58 DietPi PaperMC[15039]: at java.base/java.lang.Thread.run(Unknown Source) 
Mai 12 17:54:59 DietPi systemd1]: papermc.service: Deactivated successfully. 
Mai 12 17:54:59 DietPi systemd[1]: papermc.service: Consumed 1.203s CPU time, 397.3M memory peak.

kane6681 · 12 May 2026 16:01

Step: Installing PaperMC: Highly optimised Minecraft server with plugins, written in Java

[FAILED] DietPi-Software | Automatic latest PaperMC download URL detection failed.
[FAILED] DietPi-Software | "https://fill-data.papermc.io/v1/objects/bcf7d5a399428d252e0710de9e305935e0af0ce8b4d50fd4651bc3d6f6a320fb/paper-26.1.2-7.jar" will be used as fallback, but a newer version might be available.
[FAILED] DietPi-Software | Please report this at: 
[  OK  ] DietPi-Software | cd /tmp/DietPi-Software
[  OK  ] DietPi-Software | curl -sSfL https://fill-data.papermc.io/v1/objects/bcf7d5a399428d252e0710de9e305935e0af0ce8b4d50fd4651bc3d6f6a320fb/paper-26.1.2-7.jar -o paper-26.1.2-7.jar
[  OK  ] DietPi-Software | mv paper-26.1.2-7.jar /opt/papermc/paperclip.jar
[  OK  ] DietPi-Software | mkdir -p /mnt/dietpi_userdata/papermc
[  OK  ] DietPi-Software | eval echo 'eula=true' > /mnt/dietpi_userdata/papermc/eula.txt
[  OK  ] DietPi-Software | usermod -d /mnt/dietpi_userdata/papermc -s /usr/sbin/nologin papermc

Joulinar · 12 May 2026 16:15

soo the PaperMC version download depends on the installed java version.
If there is a version java 21 and higher, we will download latest PaperMC. If fetching the version is not working, we will fall back to PaperMC 26.1.2-7.

I would need to run some test.

Joulinar · 12 May 2026 18:03

There are 2 issues with PaperMC

there is a typo preventing the script from detecting correct url
higher java version required

We will take care on both for next release. Thy for reporting them

Jappe · 13 May 2026 10:40

But the latest paper version is 26.1.
And I have java 21, so I can not get the newst paperMC, which makes sense.

I don’t understand why he’s “falling back” to paper 26, which is the latest.
Edit: ah because of the typo. Still a bit weird why I experience a different behavior when updating.

Did you install a new Java version manually?

Joulinar · 13 May 2026 12:13

we already adjusted PaperMC install for next release

MichaIng · 13 May 2026 16:11

For reference: dietpi-software: Java: bump to latest available versions by MichaIng · Pull Request #8137 · MichaIng/DietPi · GitHub

So Java 26 will be installed from next version on. You can also do that manually:

apt install temurin-26-jre

Then adjust the java executable path in /etc/systemd/system/papermc.service:

sed -i 's/temurin-21/temurin-26/' /etc/systemd/system/papermc.service
systemctl daemon-reload
systemctl restart papermc

Multiple Java versions can be installed alongside each other. And since we use absolule paths in our systemd services, it does not affect other installed Java applications, in case.

kane6681 · 13 May 2026 16:16

Thx