Problem on iMac version of OS x leopard snow 10.6.8

@Jorgia (11)
May 26, 2017 4:37pm CST
I have a problem on iMac OS x leopard snow 10.6.8 it does not update to the latest version of OS x.It always says that there is no available update for my device.It always says that your software is updated. I am confused do i really have to purchase the next OSx version which is Mountain Lion?
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