different RLC-410-5MP versions?

[Left Coast Geek_399297764155577]

i've bought 5 RLC-410-5MP's. the first 3 were all Hardware IPC-51516M5M, and some needed upgrading to 20121100, others didn't. last 2 I bought same order from Amazon, one was IPC-515B16M5M, the other was the same as the first 3, and one needed the firmware upgrade to 20121100 before BlueIris could reliably capture video from it.

what is the difference in these cameras? Do I in fact have to use the two different firmware updates, even tho both are the same 'build' ?

[Cynthia_124785627824270]

They have different Hardware, you need to use different firmware to upgrade the cameras. Their functions are the same.