Am I able to put Ventura 13.0 or higher on my 2015 vintage iMAC? Turbo Tax 2024 will not work with Monterey 12.7.6.

The last version of Mac OS a 2015 (now obsolete and considered vintage by Apple) will run is Monterey. If you want to run TurboTax then your choices are to run the on-line version of TT or it is time to consider getting a more up-to-date computer. Your 10 year old iMac may run okay for now, however it is running on borrowed time.

Apple just released new Mac Mini's and one of those (a 1 TB version and 16GB of RAM) are an ideal Mac for everyday use. All you need to add is an external displays which can easily be found for less than $100 and you will have a new computer with a 1 year warranty, eligible for AppleCare that will FAR outperform your current iMac! Just food for thought. For less than $1300 you will have an excellent Mac that will last another decade or so.