Rudder

following error at start

2021-06-01T15:07:05.823Z] ERROR FATAL An error happen during Rudder boot. Rudder will stop now.
java.lang.AbstractMethodError: Method com/normation/rudder/ncf/TechniqueReader.com$normation$rudder$repository$xml$GitAr
chiverUtils$_setter_$semaphoreAdd_$eq(Lzio/Semaphore;)V is abstract
        at com.normation.rudder.ncf.TechniqueReader.com$normation$rudder$repository$xml$GitArchiverUtils$_setter_$semaph
oreAdd_$eq(TechniqueReader.scala)
        at com.normation.rudder.repository.xml.GitArchiverUtils.$init$(GitArchiverUtils.scala:74)
        at com.normation.rudder.ncf.TechniqueReader.<init>(TechniqueReader.scala:37)
        at bootstrap.liftweb.RudderConfig$.<clinit>(RudderConfig.scala:998)
        at bootstrap.liftweb.LiftInitContextListener.contextInitialized(LiftInitContextListener.scala:127)
        at org.eclipse.jetty.server.handler.ContextHandler.callContextInitialized(ContextHandler.java:933)
        at org.eclipse.jetty.servlet.ServletContextHandler.callContextInitialized(ServletContextHandler.java:553)
        at org.eclipse.jetty.server.handler.ContextHandler.startContext(ContextHandler.java:892)
        at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:356)
        at org.eclipse.jetty.webapp.WebAppContext.startWebapp(WebAppContext.java:1445)
        at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1409)
        at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:825)
        at org.eclipse.jetty.servlet.ServletContextHandler.doStart(ServletContextHandler.java:275)
        at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:524)
        at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72)
        at org.eclipse.jetty.deploy.bindings.StandardStarter.processBinding(StandardStarter.java:46)
        at org.eclipse.jetty.deploy.AppLifeCycle.runBindings(AppLifeCycle.java:188)
        at org.eclipse.jetty.deploy.DeploymentManager.requestAppGoal(DeploymentManager.java:513)
        at org.eclipse.jetty.deploy.DeploymentManager.addApp(DeploymentManager.java:154)
        at org.eclipse.jetty.deploy.providers.ScanningAppProvider.fileAdded(ScanningAppProvider.java:173)
        at org.eclipse.jetty.deploy.providers.WebAppProvider.fileAdded(WebAppProvider.java:447)