Try this @Merathilis

ElvUI/Libraries/LibElvUIPlugin-1.0/LibElvUIPlugin-1.0.lua

@@ -224,13 +224,18 @@ function lib:SendPluginVersionCheck(message)
 		return
 	end
 
-	local ChatType
+	local ChatType, Channel
 	if IsInRaid() then
 		ChatType = (not IsInRaid(LE_PARTY_CATEGORY_HOME) and IsInRaid(LE_PARTY_CATEGORY_INSTANCE)) and 'INSTANCE_CHAT' or 'RAID'
 	elseif IsInGroup() then
 		ChatType = (not IsInGroup(LE_PARTY_CATEGORY_HOME) and IsInGroup(LE_PARTY_CATEGORY_INSTANCE)) and 'INSTANCE_CHAT' or 'PARTY'
-	elseif IsInGuild() then
-		ChatType = 'GUILD'
+	else
+		local ElvUIGVC = GetChannelName('ElvUIGVC')
+		if ElvUIGVC and ElvUIGVC > 0 then
+			ChatType, Channel = 'CHANNEL', ElvUIGVC
+		elseif IsInGuild() then
+			ChatType = 'GUILD'
+		end
 	end
 
 	if not ChatType then
@@ -245,14 +250,14 @@ function lib:SendPluginVersionCheck(message)
 			splitMessage = strmatch(strsub(message, 1, maxChar), '.+;')
 			if splitMessage then -- incase the string is over 250 but doesnt contain `;`
 				message = gsub(message, '^'..gsub(splitMessage, '([%(%)%.%%%+%-%*%?%[%^%$])','%%%1'), '')
-				E:Delay(delay, C_ChatInfo_SendAddonMessage, lib.prefix, splitMessage, ChatType)
+				E:Delay(delay, C_ChatInfo_SendAddonMessage, lib.prefix, splitMessage, ChatType, Channel)
 				delay = delay + 1
 			end
 		end
 
 		E:Delay(delay, lib.ClearSendMessageWait)
 	else
-		C_ChatInfo_SendAddonMessage(lib.prefix, message, ChatType)
+		C_ChatInfo_SendAddonMessage(lib.prefix, message, ChatType, Channel)
 		lib.ClearSendMessageWait()
 	end
 end

ElvUI/core/core.lua

@@ -29,10 +29,9 @@ local C_ChatInfo_SendAddonMessage = C_ChatInfo.SendAddonMessage
 local UnitGroupRolesAssigned = UnitGroupRolesAssigned
 local UnitHasVehicleUI = UnitHasVehicleUI
 local GetChannelName = GetChannelName
-local JoinPermanentChannel = JoinPermanentChannel
+local JoinChannelByName = JoinChannelByName
 local UnitLevel, UnitStat, UnitAttackPower = UnitLevel, UnitStat, UnitAttackPower
 local UnitFactionGroup = UnitFactionGroup
-local GetChannelList = GetChannelList
 local IsInRaid, IsInGroup = IsInRaid, IsInGroup
 local GetNumGroupMembers = GetNumGroupMembers
 local LE_PARTY_CATEGORY_HOME = LE_PARTY_CATEGORY_HOME
@@ -914,8 +913,13 @@ function E:SendMessage()
 		C_ChatInfo_SendAddonMessage("ELVUI_VERSIONCHK", E.version, (not IsInRaid(LE_PARTY_CATEGORY_HOME) and IsInRaid(LE_PARTY_CATEGORY_INSTANCE)) and "INSTANCE_CHAT" or "RAID")
 	elseif IsInGroup() then
 		C_ChatInfo_SendAddonMessage("ELVUI_VERSIONCHK", E.version, (not IsInGroup(LE_PARTY_CATEGORY_HOME) and IsInGroup(LE_PARTY_CATEGORY_INSTANCE)) and "INSTANCE_CHAT" or "PARTY")
-	elseif IsInGuild() then
-		C_ChatInfo_SendAddonMessage("ELVUI_VERSIONCHK", E.version, "GUILD")
+	else
+		local ElvUIGVC = GetChannelName('ElvUIGVC')
+		if ElvUIGVC and ElvUIGVC > 0 then
+			C_ChatInfo_SendAddonMessage("ELVUI_VERSIONCHK", E.version, "CHANNEL", ElvUIGVC)
+		elseif IsInGuild() then
+			C_ChatInfo_SendAddonMessage("ELVUI_VERSIONCHK", E.version, "GUILD")
+		end
 	end
 
 	SendMessageWaiting = nil
@@ -939,7 +943,7 @@ local function SendRecieve(_, event, prefix, message, _, sender)
 
 					E.recievedOutOfDateMessage = true
 				end
-			elseif msg and (msg < ver) then -- Send Message Back if you intercept and are higher revision
+			elseif msg and (msg < ver) then -- Send Message Back
 				if not SendMessageWaiting then
 					SendMessageWaiting = E:Delay(10, E.SendMessage)
 				end
@@ -959,6 +963,8 @@ local function SendRecieve(_, event, prefix, message, _, sender)
 		if not SendMessageWaiting then
 			SendMessageWaiting = E:Delay(10, E.SendMessage)
 		end
+	elseif event == "PLAYER_LOGOUT" then
+		LeaveChannelByName("ElvUIGVC")
 	end
 end
 
@@ -968,8 +974,20 @@ local f = CreateFrame("Frame")
 f:RegisterEvent("CHAT_MSG_ADDON")
 f:RegisterEvent("GROUP_ROSTER_UPDATE")
 f:RegisterEvent("PLAYER_ENTERING_WORLD")
+f:RegisterEvent("PLAYER_LOGOUT")
 f:SetScript("OnEvent", SendRecieve)
 
+hooksecurefunc("CreateChatChannelList", function()
+	if #CHAT_CONFIG_CHANNEL_LIST >= 1 then
+		if GetChannelName('ElvUIGVC') == 0 and ChatFrame_CanAddChannel() == true then
+			JoinChannelByName('ElvUIGVC', nil, nil, true)
+			if not SendMessageWaiting then
+				SendMessageWaiting = E:Delay(10, E.SendMessage)
+			end
+		end
+	end
+end)
+
 function E:UpdateAll(ignoreInstall)
 	if not self.initialized then
 		C_Timer_After(1, function() E:UpdateAll(ignoreInstall) end)