I have followed: https://confluence.atlassian.com/display/UPM/Updating+the+Universal+Plugin+Manager#UpdatingtheUniversalPluginManager-UpdatingUPMbyfilereplacement
but can't find the necessary file/directory... here is a listing from our install:
1. Shut down JIRA.
2. Remove the existing UPM JAR file from this directory in your JIRA home directory:
plugins/installed-plugins
root@libertine jira # pwd
/opt/atlassian/jira
root@libertine jira # ls
atlassian-jira conf install.reg lib logs README.html temp uninstall work
bin external-source jre licenses NOTICE README.txt tomcat-docs webapps
only thing I can find is:
root@libertine atlassian # find . -name *manager-plugin* -print
./jira/temp/plugin.9128344300493221488.atlassian-universal-plugin-manager-plugin-2.7.8.jar
./jira/temp/plugin.4566108212679965318.atlassian-universal-plugin-manager-plugin-2.7.4.jar
./jira/temp/plugin_2277919877510818531_atlassian-universal-plugin-manager-plugin-2.7.10.jar
./jira/temp/plugin.1004167666862049989.atlassian-universal-plugin-manager-plugin-2.7.7.jar
./jira/temp/plugin.6918099885958475159.atlassian-universal-plugin-manager-plugin-2.7.10.jar
./jira/temp/plugin.3400594829461404923.atlassian-universal-plugin-manager-plugin-2.7.6.jar
./jira/temp/plugin_5802223886689695509_atlassian-universal-plugin-manager-plugin-2.7.3.jar
./jira/temp/plugin.186931797163260671.atlassian-universal-plugin-manager-plugin-2.7.10.jar
./jira/temp/plugin.8533881726362717366.atlassian-universal-plugin-manager-plugin-2.7.10.jar
./jira/temp/plugin_281981356399172753_atlassian-universal-plugin-manager-plugin-2.7.10 (1).jar
./jira/temp/plugin.9180641765973393633.atlassian-universal-plugin-manager-plugin-2.7.6.jar
./jira/temp/plugin.6185725129814945694.atlassian-universal-plugin-manager-plugin-2.7.10.jar
just don't know where to pop the new jar file and don't want to break Jira 
Thanks
Richard