7.0.4.1 doesn't work for me, I still have:

[...]
013-10-08 16:57:02,928 http-bio-8080-exec-14 ERROR Chris 1017x30285x1 170t50c 192.168.2.75,127.0.0.1 /rest/plugins/1.0/com.atlassian.jira.plugin.ext.bamboo-key [plugin.osgi.factory.OsgiPlugin] Detected an error (BundleException) enabling the plugin 'com.atlassian.jira.plugin.ext.bamboo' : Unresolved constraint in bundle com.atlassian.jira.plugins.jira-bamboo-plugin [74]: Unable to resolve 74.0: missing requirement [74.0] package; (&(package=com.atlassian.jira)(version>=6.1.0.202832)).  This error usually occurs when your plugin imports a package from another bundle with a specific version constraint and either the bundle providing that package doesn't meet those version constraints, or there is no bundle available that provides the specified package. For more details on how to fix this, see https://developer.atlassian.com/x/mQAN
2013-10-08 16:57:02,930 http-bio-8080-exec-14 WARN Chris 1017x30285x1 170t50c 192.168.2.75,127.0.0.1 /rest/plugins/1.0/com.atlassian.jira.plugin.ext.bamboo-key [plugin.osgi.factory.OsgiPlugin] Unable to enable plugin 'com.atlassian.jira.plugin.ext.bamboo'
2013-10-08 16:57:02,930 http-bio-8080-exec-14 WARN Chris 1017x30285x1 170t50c 192.168.2.75,127.0.0.1 /rest/plugins/1.0/com.atlassian.jira.plugin.ext.bamboo-key [plugin.osgi.factory.OsgiPlugin] Because of this exception
com.atlassian.plugin.osgi.container.OsgiContainerException: Cannot start plugin: com.atlassian.jira.plugin.ext.bamboo
[...]
Caused by: org.osgi.framework.BundleException: Unresolved constraint in bundle com.atlassian.jira.plugins.jira-bamboo-plugin [74]: Unable to resolve 74.0: missing requirement [74.0] package; (&(package=com.atlassian.jira)(version>=6.1.0.202832))
[...]

I'm running Jira v6.1#6144-sha1:2e50328

JBAM 7.0.4.1 has been released.
Unfortunately, UPM don't allow easy update as this is bundled plugin (not a question of 4 digit number).

So, it has to be installed using "Upload add-on" button.
Easiest way is to upload form url: https://marketplace.atlassian.com/download/plugins/com.atlassian.jira.plugin.ext.bamboo/version/510

(see attached picture).

mwent can you update this issue as you make progress on building and testing the new plugin version. thanks.

the suggestion is that you rebuild a version of this plugin off the 7.0.4 tag with a change to the jira.version, setting it equal to 6.1.

this can be done now that the JIRA 6.1 bits are in maven.

this version of the plugin (7.0.4.1) then needs to be put on market place (https://marketplace.atlassian.com/plugins/com.atlassian.jira.plugin.ext.bamboo). Please confirm that you have all the necessary rights to update marketplace.

please ensure that you set the JIRA compatibility of this plugin to 6.1 so that old JIRA installs do not try and upgrade to it.

we will mention this in the JIRA 6.1 release notes / upgrade notes and we will tell people to upgrade to this version via UPM. So you need to test running up a new JIRA 6.1 install, seeing that JBAM is not started, then upgrading via UPM to 7.4.0.1 and seeing that it becomes enabled.

From the manifest

com.atlassian.jira;version="6.1.0.202832",
com.atlassian.jira.bc.project.component;version="6.1.0.202832",
com.atlassian.jira.component;version="6.1.0.202832",
com.atlassian.jira.config.properties;version="6.1.0.202832",
com.atlassian.jira.event;version="6.1.0.202832",
com.atlassian.jira.event.type;version="6.1.0.202832",
com.atlassian.jira.extension;version="6.1.0.202832",
com.atlassian.jira.issue;version="6.1.0.202832",
com.atlassian.jira.issue.link;version="6.1.0.202832",
com.atlassian.jira.issue.search;version="6.1.0.202832",
com.atlassian.jira.jql.builder;version="6.1.0.202832",
com.atlassian.jira.plugin.issuetabpanel;version="6.1.0.202832",