Enjoy your new iMac and Yosemite. While you are waiting for it to be delivered it would be an opportune time to be sure all and I mean ALL of your applications, kexts, etc. are up to date and make a list of those you will need to update after you are running Yosemite. The most common glitch with Yosemite is out of date software. I have been doing this for a few weeks. I have a list of updates that can be downloaded when I get Yosemite and I just ordered new calibration software from Xrite (the old software is PPC only). Most of my apps will work and, luckily, I rarely (if ever) use a lot of the ones that won't. I will be trashing the useless apps before migrating. There's no sense wasting time and disk space on them.
Jon
macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365
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