[logback-user] Upgrading Logback Classic from 1.3.8 to 1.3.9 causes ClassNotFoundException: ch.qos.logback.classic.spi.Configurator

dcmoeller at gmx.de dcmoeller at gmx.de
Wed Aug 9 08:44:29 CEST 2023

Hello everybody,

this morning weekly build of our software breaks with


As we configure Gradle to apply


this build receives new patch level version 1.3.9, published a few days ago.

I've downloaded both versions, 1.3.8 and 1.3.9, of the lib from [1],
missing class is available with 1.3.8, but missing in 1.3.9.

General remark: I do not expect such a modification with patch level

My question: Is this a bug on your side, or have I missed some
deprecation announcement explaining how to reconfigure Logback, or apply
another Logback lib, or the like to avoid this problem?

Thanks and regards


[1] https://mvnrepository.com/artifact/ch.qos.logback/logback-classic

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