snow leopard to mavericks

Logic Pro 9 shows 10.6.8 and above

Logic Pro 9 - Technical Specifications

however any 3rd party plug-in will require their developers to make a compatible version. Apple does not fix their software to allow someone elses code to run in the event the update makes it incompatible.

Before any upgrade it is advised you backup your system as it is currently configured.

Use Time Machine to back up or restore your Mac - Apple Support

You won’t need to reinstall the software unless a problem occurs, but may need to upgrade or replace it. Click here and check.

Note that you won’t be able to upgrade the OS from a download on Apple’s Support site. You need to perform the upgrade from the Mac App Store or a thumbdrive.

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OS X 10.9 Mavericks is no longer available for initial download from the Mac App Store

Hasn't been available for a long time.

You either need to pay for a special download code for both OS X 10.7 Lion or , if your Mac hardware qualfies, OS X 10.8 Mountain Lion OR the free macOS Sierra, or, possibly, OS X 10.11 El Capitán.

You maybe able to obtain OS X 10.9.5 Mavericks from your "local" Apple Store or an authorised Apple dealer/service center.

You would have to call them, first, to see if they are able to do this.

Upgrading/Updating your Mac OS

Check that your computer is compatible with Mountain Lion/Mavericks/Yosemite/El Capitan.

To check the model number hold down the option/alt key, go to the Apple menu and select System Information.

iMac (Mid 2007 or newer) model number 7,1 or higher

macOS 10.12 (Sierra) requires one of the following Macs:

iMac (Late 2009 or later)

El Capitan 10.11 Compatibility information

macOS Sierra 10.12: Compatible Apps

Also check to make sure there is a compatible driver for your printer.

Do a backup before installing, preferable 2 backups on 2 different drives.