I would say to be safe make a backup of your HDD or just the data you want to keep just in case the OS has a panic attack.
I was thinking of upgrading my i5 4460 to a i7 4790 but I didn't think it was worth £240+ just so I could have a higher clock and 8 threads as the i5 4460 is the most commonly used i5 out there and is very strong in its own right, so I replaced my PSU and ordered an SSD and an OS to put on the SSD.
There shouldn't be any problems as I do believe the i5 4460 and i7 use the same HD graphics version, that's the only thing that would be a problem if they weren't the same.
Also as long as you have a decent room temperature or CPU cooler you should be fine temp wise as the i7 can run rather hot due to how hard it can work if you somehow manage to get it to near full usage, I would say a safe temp at load for Intel CPU's is 60 celsuis, 70 and the CPU will probably clock down so not to overheat as that what my i5 did when we had a random huge heat wave last year for a few days and i'm in Britain but usually its 30-60 with an hardly audible noise.