Ok, so I just downloaded the Valentines Day update and I found that I could not visit neighbours whom I know have also updated so I let the device (my iPhone) shut down and then restarted it and started up the game again and then I was able to visit several of my neighbours, but not all of them. So my advice is, after updating let the device shut down or you might try logging out of Origin and then back in to 'wake-up' the program.
I hope this helps other people who are having trouble getting the game to recognize neighbours who also have updated the game.
I hope this helps other people who are having trouble getting the game to recognize neighbours who also have updated the game.