When I run the following on a wireguard instance
wireguard@lists.zx2c4.com
    wg set wg0 peer *SOMEPUB1* allowed-ips 0.0.0.0/0 persistent-keepalive 25
    wg set wg0 peer *SOMEPUB2* allowed-ips 0.0.0.0/0 persistent-keepalive 25

only the last key gets set with an allowed-ips directive

interface: wg0
  public key: *HOSTKEY*
  private key: (hidden)
  listening port: 51820

peer: *SOMEPUB2*
  endpoint: *SOMEIP*:38568
  allowed ips: 0.0.0.0/0
  latest handshake: 1 minute, 11 seconds ago
  transfer: 4.81 KiB received, 3.47 KiB sent
  persistent keepalive: every 25 seconds

peer: *SOMEPUB1*
  endpoint: *SOMEIP*:36411
  allowed ips: (none)         #<< This appears wrong
  latest handshake: 1 minute, 24 seconds ago
  transfer: 44.05 KiB received, 47.68 KiB sent
  persistent keepalive: every 25 seconds

I cannot pass traffic from SOMEPUB1, and no handshake occurs

if SOMEPUB1 occurs last in the sequence of running wg set commands, it
retains the allowed-ips configuration and it CAN pass traffic, so it seems
only the last command run for me is valid for allowed-ips

the host is running the following
ii  wireguard-dkms                      0.0.20171111-wg1~zesty
all          fast, modern, secure kernel VPN tunnel (DKMS version)
ii  wireguard-tools                     0.0.20171111-wg1~zesty
amd64        fast, modern, secure kernel VPN tunnel (userland utilities)

one of the peers is running the same, the other is a rasberry pi built from
source snapshot as described on wireguard.com (WireGuard-0.0.20171111)

Am I missing something or is there an issue with configuring 2 peers with
0.0.0.0/0 in this release?

Thanks in advance