It's basically in the question - I have the old ISY z-wave module and I had two Aeon DSD37 Repeaters with 3 Schlage 469 locks (older type).  Never worked that great.  I removed the repeaters this weekend after reading the forums which indicated that they don't help.  (is this true?)  After some further reading, I pulled data sheets from z-wave alliance and the locks apparently have zwave (1-beaming, 2-network security, 3-AES-128 Security S0).  The DSD37s have 1 and 2, but not 3.  Would a device require AES-128 Security S0 in order to be able to act as a repeater to improve range of the locks?  I think I will eventually need about 3 compatible plug-in devices to improve performance - I got one Aeotec Gen5 Siren which seems to improve performance a bit and have ordered an Aeotec Gen6 repeater - both have 1,2,3, but I also ordered a Jasco Single Plug-In module which only has 1,2 so I am wondering if that is not going to be able to help the network. 

So, would compatible plug-in devices require all 1,2,3 to act as a compatible repeater?

Thanks in advance for your advice.

I'm not sure specifically if it's required, but the Ring extenders offer S2 support as well so they're probably your best bet.

Thanks but I think that S2 is for the newer zwave plus equipment only, in my case, the zwave locks can only do the 3 things that I listed (S2 not supported) - I think that I have read enough to conclude that beaming is definitely required to talk to the locks, but not 100% sure if items 2 and/or 3 required.  If only 2 is required, then the DDS37s would actually help.

Any device that supports beaming will work. These can be outlets, lamp modules, switches etc. Personally, I wouldn't buy a repeater. I'd get devices that would allow me to control other stuff such as lamp modules.

Assuming you need only 3 devices also sets you up for failure. Due to how zwave (wireless in general) works, you're better off having more than what you think you need (not saying you need 10 devices) than shooting for the bare minimum

I can confirm that the DSD37 devices made things worse for me - but I use Kwikset locks.