After some upgrades it may be necessary to retag the content - have it parsed for tags and other metadata. This would usually be only if improvements have been made to Jiglu's internal Dynamic Discovery Engine algorithms and will be noted in the version release notes.
You first need to connect with MultiTool, choose the Contribution menu option, then the Retag everything option. When source items are retagged they may need to be redownloaded so if you do not want this then instead choose the Retag everything internal option. You can monitor the progress of retagging in the system logs.
The contribution menu also provides options to retag an individual group, contribution, view the tag metadata for a particular contribution and purge over-quota content when groups have quotas enabled.