Going to buy new 21.5 Retina iMac. display question

[gelie]

Is there a way to use my current 21.5 mid 2010 iMac as a additional display off the new one?

 

[Fl0r!an]

On pre-Thunderbolt Macs (like yours), Target Display mode is only supported on the 27" models. So no, sadly not.

The good news: When you sell your current iMac, you can easily buy some new displays

 

[Samuelsan2001]

Is there a way to use my current 21.5 mid 2010 iMac as a additional display off the new one?

You might want to wait the next lot of 21 inch iMacs will be 4K displays and should be out this month.

Sorry just seen the retina in the title please ignore.