It is perfectly safe to click okay on this window and allow i Tunes to install, so long as you downloaded the i Tunes installer directly from Apple, or are using Apple's Software Update program!
If you downloaded the installer from another source, I would recommend clicking 'Cancel' and getting another copy of i Tunes from Apple directly at (which will also provide you with the most up to date installer).
In addition to opening i Tunes on your computer and checking for an update there, you can also download an i Tunes update on Apple’s website.
When you’re on Apple’s website, you can also check the system requirements for the i Tunes update you need to download, and review whether your system meets the requirements for the features that you want to use.
Currently, the basic requirements for an i Tunes update for Mac include OS X version 10.8.5 or later (and Apple Music requires OS X version 10.9.5 or later), plus 400MB of available disk space.
Before you begin, make sure you download the Sonos Desktop Controller App for Mac or PC and install it on the computer that contains your music library files.
Whenever you make changes to your music library, such as adding and removing tracks, creating new playlists, or adjusting album artwork, you will need to update the music index on Sonos before these changes will show up in the Sonos controller.
Then, you can follow the prompts to install the latest version.