Apple has released an updated version of iTunes through the Mac App Store, although the version number and release notes appear the same.
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iTunes 12.6.1 with ‘minor app and performance improvements’ was first released last Monday with no visible changes, but Apple has issued a new iTunes update through the Mac App Store today without changing the version number or change log.
The new iTunes 12.6.1 update does have a slightly higher build number at 22.214.171.124 compared to 126.96.36.199 on the previous release, although any changes are likely very minor considering the version number going unchanged.
You can grab the latest update to iTunes through the Mac App Store.