Our jobs are mostly all configured to use a common "template" project that has a stock set of publishers defined, including publishing artifacts to artifactory via the plugin.

When we upgraded to the lasted version of Artifactory all our builds started failing with a NullPointer exception in the plugin:

ERROR: Build step failed with exception
java.lang.NullPointerException
at org.jfrog.hudson.ArtifactoryServer.setRetryParams(ArtifactoryServer.java:268)
at org.jfrog.hudson.ArtifactoryServer.createArtifactoryClient(ArtifactoryServer.java:251)
at org.jfrog.hudson.ArtifactoryRedeployPublisher.perform(ArtifactoryRedeployPublisher.java:432)
at hudson.plugins.templateproject.ProxyPublisher.perform(ProxyPublisher.java:85)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:779)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:720)
at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.post2(MavenModuleSetBuild.java:1067)
at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:665)
at hudson.model.Run.execute(Run.java:1753)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:544)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:404)

I'm going to hazard a guess it is related to the fix for: https://www.jfrog.com/jira/browse/HAP-855