No ESXi, only windows.
As i correctly you understand build 12767 also have "supplementary" sessions, but not shown in gui console?
But..
From log file with build 12767:
3/3 23:59:18.402245 1020 Common: *** MountTarget: (session(0000010514EFB580), local(0.0.0.0), peer(10.98.4.12), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/3 23:59:18.402314 1028 Common: *** MountTarget: (session(0000010514EFBB10), local(0.0.0.0), peer(10.98.5.4), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/3 23:59:18.402920 1024 Common: *** MountTarget: (session(0000010514EFBD60), local(0.0.0.0), peer(10.98.4.28), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/3 23:59:18.402980 102c Common: *** MountTarget: (session(0000010514F4B5A0), local(0.0.0.0), peer(10.98.5.20), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/3 23:59:18.416187 1030 Common: *** MountTarget: (session(0000010514F5BC10), local(0.0.0.0), peer(192.168.255.170), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/3 23:59:18.430502 fe4 func: <<< CHADevice::CreateDevice
No more mount targets for target "iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2".
From log file with 13481 build:
3/5 10:08:07.159047 1c18 Common: *** MountTarget: (session(000002A196628200), local(0.0.0.0), peer(10.98.4.12), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/5 10:08:07.168528 14fc Common: *** MountTarget: (session(000002A196620C30), local(0.0.0.0), peer(10.98.4.28), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/5 10:08:07.172292 1c18 Common: *** MountTarget: (session(000002A1965FDA50), local(0.0.0.0), peer(10.98.4.12), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/5 10:08:07.176927 1860 Common: *** MountTarget: (session(000002A196631070), local(0.0.0.0), peer(10.98.5.4), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/5 10:08:07.178626 14fc Common: *** MountTarget: (session(000002A196602EC0), local(0.0.0.0), peer(10.98.4.28), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/5 10:08:07.183940 1c18 Common: *** MountTarget: (session(000002A196627FB0), local(0.0.0.0), peer(10.98.4.12), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/5 10:08:07.189826 1860 Common: *** MountTarget: (session(000002A19666D400), local(0.0.0.0), peer(10.98.5.4), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/5 10:08:07.190418 14fc Common: *** MountTarget: (session(000002A19669EEE0), local(0.0.0.0), peer(10.98.4.28), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/5 10:08:07.190970 1b30 conf: ConfAclCommand::processNew: Acl record 'allow for partner(s) of iqn.2008-08.com.starwindsoftware:localhost-witfx2-fx1' loaded successfully.
3/5 10:08:07.191168 1c28 func: <<< HASyncNode::createDevice
3/5 10:08:07.192427 1d5c Common: *** MountTarget: (session(000002A1966D09D0), local(0.0.0.0), peer(10.98.5.20), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/5 10:08:07.193399 1c28 SCSI: iScsiDevice::updateDeviceIds: EUI64 retrieved: C3EF40B87747B60E (hex)
3/5 10:08:07.203326 238 Common: *** MountTarget: (session(000002A196619E20), local(0.0.0.0), peer(192.168.255.170), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/5 10:08:07.208509 1d5c Common: *** MountTarget: (session(000002A196653430), local(0.0.0.0), peer(10.98.5.20), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
3/5 10:08:07.218207 238 Common: *** MountTarget: (session(000002A1967303F0), local(0.0.0.0), peer(192.168.255.170), port(3260), target(iqn.2008-08.com.starwindsoftware:192.168.254.27-witfx2-fx2).
As result it 12 sessions, but configured 5.
Ok, supplementary sessions for boost start showing in build 13481, but why they have only 12 connections (16 - 4(customers) = 12)?.
Via netstat -an | sls 3260| sls 10.98.4.11 = i see 9 connections from each side (for sync channel between 10.98.4.11 and 10.98.4.12):
PS C:\Users\gklpnd> netstat -an | sls 3260 | sls 10.98.4.1
TCP 10.98.4.11:3260 0.0.0.0:0 LISTENING
TCP 10.98.4.11:3260 10.98.4.12:50180 ESTABLISHED
TCP 10.98.4.11:3260 10.98.4.12:50185 ESTABLISHED
TCP 10.98.4.11:3260 10.98.4.12:50186 ESTABLISHED
TCP 10.98.4.11:3260 10.98.4.12:50191 ESTABLISHED
TCP 10.98.4.11:3260 10.98.4.12:50197 ESTABLISHED
TCP 10.98.4.11:3260 10.98.4.12:50201 ESTABLISHED
TCP 10.98.4.11:3260 10.98.4.12:50202 ESTABLISHED
TCP 10.98.4.11:3260 10.98.4.12:50205 ESTABLISHED
TCP 10.98.4.11:3260 10.98.4.12:50206 ESTABLISHED
TCP 10.98.4.11:63033 10.98.4.12:3260 ESTABLISHED
TCP 10.98.4.11:63035 10.98.4.12:3260 ESTABLISHED
TCP 10.98.4.11:63038 10.98.4.12:3260 ESTABLISHED
TCP 10.98.4.11:63045 10.98.4.12:3260 ESTABLISHED
TCP 10.98.4.11:63046 10.98.4.12:3260 ESTABLISHED
TCP 10.98.4.11:63049 10.98.4.12:3260 ESTABLISHED
TCP 10.98.4.11:63057 10.98.4.12:3260 ESTABLISHED
TCP 10.98.4.11:63058 10.98.4.12:3260 ESTABLISHED
TCP 10.98.4.11:63062 10.98.4.12:3260 ESTABLISHED
You still can get rid of those 2008 connections by modifying the .swdsk and _HA.swdsk files (i do not recommend doing that though).
Do you mean data/control connections (sync and hb)?