Apple has posted iTunes 12.3, which adds support for iOS 9 and Mac OS X El Capitan, which is coming later this month.
According to Apple, the upgrade also:
° Offers improved Apple Music accessibility with VoiceOver;
° Resolves a problem that prevented ordering of songs within Up Next;
° Fixes a problem where some radio stations did not appear within Recently Played;
° Addresses an issue where songs you loved on iOS did not appear loved on iTunes;
° Supports two-factor authentication to secure your Apple ID;
° Includes improvements to overall stability and performance.
You can download iTunes 12.3 via the Software Update option in the Mac App Store or from the iTunes website.