I’ve never had any issues with this release (bin files at the bottom of the page):
Hi @tom_l I just downgraded one of my switches to the version you linked to.
But I still get : Client Sonoff_S20_1 has exceeded timeout, disconnecting.
I don’t know if this is calls for a total reflash by cable for all my switches…
I just downgraded by the web UI on the switch worked ok
Could be a problem with your broker set up.
@tom_l First thanks for helping! much appriciated
I am using the standard “Mosquitto broker” and must admit besides updating it regularly I haven’t made any changes to it. I did update the Hassio to the new 0.100 but I have not seen any other complaining so I dont think thats the issue.
I have tried so many thinks updating the Unifi wifi software, different versions of Tasmota
Sofar its just buggy and slow to respond also connecting to the native Tasmota UI on the switch itself, that is why I keep ending up looking at the firmware
Looking at the Mosquitto log file I see this over and over for all devices:
1571833265: New client connected from 192.168.0.6 as Sonoff_S20_1 (p2, c1, k15, u'casperse').
1571833274: Client Sonoff_S20_2 has exceeded timeout, disconnecting.
1571833308: Client Sonoff_S20_1 has exceeded timeout, disconnecting.
1571833315: New connection from 192.168.0.6 on port 1883.
1571833315: New client connected from 192.168.0.6 as Sonoff_S20_2 (p2, c1, k30, u'casperse').
1571833368: New connection from 192.168.0.6 on port 1883.
1571833368: New client connected from 192.168.0.6 as Sonoff_S20_1 (p2, c1, k15, u'casperse').
1571833412: Client Sonoff_S20_2 has exceeded timeout, disconnecting.
1571833413: New connection from 192.168.0.6 on port 1883.
1571833413: New client connected from 192.168.0.6 as Sonoff_S20_2 (p2, c1, k30, u'casperse').
1571833427: Client Sonoff_S20_1 has exceeded timeout, disconnecting.
1571833474: New connection from 192.168.0.6 on port 1883.
1571833474: New client connected from 192.168.0.6 as Sonoff_S20_1 (p2, c1, k15, u'casperse').
1571833508: Client Sonoff_S20_2 has exceeded timeout, disconnecting.
1571833513: New connection from 192.168.0.6 on port 1883.
1571833513: New client connected from 192.168.0.6 as Sonoff_S20_2 (p2, c1, k30, u'casperse').
1571833562: Client Sonoff_S20_2 has exceeded timeout, discon
I really don’t know what to try next so any suggestion is most welcome
Thanks!
How have you defined your mqtt user?
It is a local user (defined in the Mosquitto addon config only) or a home assistant user?
I flashed a LSC GU10 light bulb with tasmota 6.6.0.18, frequent disconnects. Then I updated (OTA) to 6.6.0.18 with 2.3.0 core, did not have a disconnect in 14 days.
I had problems previously when connecting my Pi via wifi.
Although it was in the same room as the router and the connection seemed stable MQTT just didn’t like it at all and would constantly disconnect and reconnect devices.
Since repositioning the Pi in my TV cupboard and using ethernet the connections have been rock solid.
Using 3 Tasmota’d LED RGB controllers at the moment.
That did it! I just tried the newest version on http://thehackbox.org/tasmota/
And updating 3 of my switches to this version build on the 2.3.0 core and they just worked again!
wifi experience is still a little low:
But Wifi as reported by the switches seems okay 88%-88%-90%
The 0ebec1f-sonoff does not give any disconnects!
The other ones does!
And the nice thing is that I can update them through the UI (If I can upload the bin between disconnects)
Thanks everyone that made my whole month! - Family is used to be able to use Google assistant!
My Tasmota flashed Sonoff devices work great, no issues with wifi disconnects myself. I’m using core 2.4.2 to build the firmware.
Well, mileage can vary. Every time I try anything else but core 2.3.0 I get frequent disconnects. Maybe I just have to many wifi devices in the house. A quick count. 10x shelly 1, 7x sonoff mini, 15x sonoff basic, 2x sonoff rf bridge, 2x rflink with esprflink, 2x sonoff 4ch pro, 1 sonoff 4ch, 1 sonoff powr2, 1 sonoff rf, 1 gui10 bulb, 3 desktops, 3 laptops, 2 android tv sticks, 2 phones, 3 android tablets, 1 zigbee coordinator with esp, and probably some I forgot. And a lot of zigbee devices that use 2.4 too.
Serious stuff here 
What router and AP are you using BTW?
Router is a TP-Link flashed with openwrt, AP are 3 routers flashed with DD-wrt used as AP.
One thing I noticed might not be related but after flashing all my Tasmota to the working firmware I noticed a disconnect of a device I dont know? The IP is for the host of the VM running the Hassio?
(I have been running on Raspberry for years, but this really gives performance like nothing else)
Anyway I get these:
1571853510: New connection from 192.168.0.6 on port 1883.
1571853510: Client DVES_87316A already connected, closing old connection.
1571853510: New client connected from 192.168.0.6 as DVES_87316A (p2, c1, k30, u'casperse').
1571853537: Socket error on client DVES_87316A, disconnecting.
1571853538: New connection from 192.168.0.6 on port 1883.
1571853538: New client connected from 192.168.0.6 as DVES_87316A (p2, c1, k30, u'casperse').
1571853553: Socket error on client DVES_87316A, disconnecting.
I don’t know what “DVES_87316A” is? - (Not a big problem, just curious…)
That’s possibly the worst core ever released! You’re one of the few it works for. 2.3 has always been stable for me but I am now using pre-2.6 and have not had a single dropout in months.
Pretty sure the dev binaries @ Tasmota all use this pre 2.6 core now as well. They have even removed 2.3, 2.42 and 2.52 from platformio.ini and made 2.6 the default. (Or maybe the just give a warning) The hackbox with the dev bins only have 2.6 now as well.
Core 2.4.2 on Tasmota v6.6 stable works pretty well for me! I’m using it on the 10+ Sonoff devices I’ve flashed so far.
I’m prefer the stable branch when building my firmware, I’m not really ready to experiment with flashing dev versions as I need reliability and don’t want to risk bricking.
I did try building with core 2.3 but the flash files were too large at 550K, but I was able to use core 2.4.2 in order to get 498K flash file, I’m using MQTTs which uses quite a bit of extra code.
I’ll have to try Esp8266 core pre 2.6.x once Tasmota 6.7 is released, but I’ll wait for the stable release before flashing.
Tomorrow and core 2.6.0 will be the default. There is only one other user I am aware of who has no problems with 2.4.2 lol. Most people get constant MQTT and WiFi disconnects with core 2.4.2. Core 2.3.0 was rock solid for me and 2.6.0 hasn’t missed a beat either and it comes without the security/mesh issues of either of the other cores.
I do have a bit of an odd wifi setup, multiple wifi access points and not your typical MQTT setup, so I guess I must be one of the lucky few with core 2.4.2 currently working. 
I didn’t know that 6.7 is due out tomorrow, I did see the ‘release-6.7’ branch so guessed it would be out soon but not that soon.
yeah tomorrow. announced on their discord channel. It’s totally solid
I also have multiple access points and use mesh as well as I use a FritzBob - all or which are supposedly problems with core 2.3.0 but it was always perfect for me. When they released a version with core 2.4.2 - that was misery until I found out they had switched cores! Then 6.6.x they went back to core 2.3.0 as default again. Did their rep a lot of damage 2.4.2! Anyway, 2.6.0 is great and will be the release tomorrow. It’s already the only core in the dev builds - can’t even d/l prebuilt binaries for older cores now. My binaries (I use platformIO to roll my own) are around 462kb in size so I don’t need to screw with minimal for OTA flashing anyway.
Just upgraded one of my sonoff basics to 6.7 with the 2.6 core and it got stuck in minimal. Had to resort to a cable flash and it now works great. Anyone else had issues upgrading? Mine was previously on 6.6 with 2.3 core.
No issues OTA with 8 devices I updated.