diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index ff090e0..f181b6e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -9,7 +9,7 @@ jobs:
     timeout-minutes: 10
     strategy:
       matrix:
-        ENGINE_VERSION: [5.0.0, 5.1.0, 5.2.0, 5.3.0, 5.4.0, 5.5.0, 5.6.0, 5.6.1, latest]
+        ENGINE_VERSION: [5.0.1, 5.1.1, 5.2.0, 5.3.0, 5.4.1, 5.5.1, 5.6.1, 5.7.0, latest]
 
     steps:
     - uses: actions/checkout@v3
diff --git a/docker-compose.yml b/docker-compose.yml
index 865f083..f7f9976 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -5,7 +5,7 @@ services:
   build:
    context: ./test
    args:
-    ENGINE_VERSION: ${ENGINE_VERSION:-5.5.0}
+    ENGINE_VERSION: ${ENGINE_VERSION:-5.7.0}
   user: root
   volumes:
     - "./:/root/.minetest/worlds/world/worldmods/mail/"
diff --git a/gui.lua b/gui.lua
index 9607771..d1dca04 100644
--- a/gui.lua
+++ b/gui.lua
@@ -1,77 +1,4 @@
 
-function mail.compile_contact_list(name, selected, playernames)
-	-- TODO: refactor this - not just compiles *a* list, but *the* list for the contacts screen (too inflexible)
-	local formspec = {}
-	local contacts = mail.get_contacts(name)
-
-	if playernames == nil then
-		local length = 0
-		for k, contact, i, l in mail.pairsByKeys(contacts) do
-			if i == 1 then length = l end
-			formspec[#formspec + 1] = ","
-			formspec[#formspec + 1] = ","
-			formspec[#formspec + 1] = minetest.formspec_escape(contact.name)
-			formspec[#formspec + 1] = ","
-			local note = contact.note
-			-- display an ellipsis if the note spans multiple lines
-			local idx = string.find(note, '\n')
-			if idx ~= nil then
-				note = string.sub(note, 1, idx-1) .. ' ...'
-			end
-			formspec[#formspec + 1] = minetest.formspec_escape(note)
-			if type(selected) == "string" then
-				if string.lower(selected) == k then
-					selected = i
-				end
-			end
-		end
-		if length > 0 then
-			if selected and type(selected) == "number" then
-				formspec[#formspec + 1] = ";"
-				formspec[#formspec + 1] = tostring(selected + 1)
-			end
-			formspec[#formspec + 1] = "]"
-		else
-			formspec[#formspec + 1] = "]label[2,4.5;No contacts]"
-		end
-	else
-		if type(playernames) == "string" then
-			playernames = mail.parse_player_list(playernames)
-		end
-		for i,c in ipairs(playernames) do
-			formspec[#formspec + 1] = ","
-			formspec[#formspec + 1] = ","
-			formspec[#formspec + 1] = minetest.formspec_escape(c)
-			formspec[#formspec + 1] = ","
-			if contacts[string.lower(c)] == nil then
-				formspec[#formspec + 1] = ""
-			else
-				local note = contacts[string.lower(c)].note
-				-- display an ellipsis if the note spans multiple lines
-				local idx = string.find(note, '\n')
-				if idx ~= nil then
-					note = string.sub(note, 1, idx-1) .. ' ...'
-				end
-				formspec[#formspec + 1] = minetest.formspec_escape(note)
-			end
-			if not selected then
-				if type(selected) == "string" then
-					if string.lower(selected) == string.lower(c) then
-						selected = i
-					end
-				end
-			end
-		end
-		if #playernames > 0 and selected and type(selected) == "number" then
-			formspec[#formspec + 1] = ";"
-			formspec[#formspec + 1] = tostring(selected + 1)
-		end
-		formspec[#formspec + 1] = "]"
-	end
-	return table.concat(formspec, "")
-
-end
-
 if minetest.get_modpath("unified_inventory") then
 	mail.receive_mail_message = mail.receive_mail_message ..
 		" or use the mail button in the inventory"
diff --git a/init.lua b/init.lua
index 283e7c6..a8f0951 100644
--- a/init.lua
+++ b/init.lua
@@ -38,6 +38,7 @@ end
 -- sub files
 local MP = minetest.get_modpath(minetest.get_current_modname())
 dofile(MP .. "/util/normalize.lua")
+dofile(MP .. "/util/contact.lua")
 dofile(MP .. "/util/uuid.lua")
 dofile(MP .. "/chatcommands.lua")
 dofile(MP .. "/migrate.lua")
diff --git a/test/Dockerfile b/test/Dockerfile
index 9c1bd1b..472255d 100644
--- a/test/Dockerfile
+++ b/test/Dockerfile
@@ -1,4 +1,4 @@
-ARG ENGINE_VERSION=5.5.0
+ARG ENGINE_VERSION=5.7.0
 FROM registry.gitlab.com/minetest/minetest/server:${ENGINE_VERSION}
 
 # copy old v1 maildb for migration testing
@@ -7,11 +7,9 @@ COPY ./mail.db /root/.minetest/worlds/world/mail.db
 COPY ./old_v2_player.json /root/.minetest/worlds/world/mails/
 COPY ./auth.sqlite /root/.minetest/worlds/world/auth.sqlite
 
-
 USER root
 RUN apk add git &&\
     mkdir -p /root/.minetest/worlds/world/worldmods/ &&\
     git clone https://github.com/BuckarooBanzay/mtt /root/.minetest/worlds/world/worldmods/mtt
 
-
 ENTRYPOINT minetestserver --config /minetest.conf
\ No newline at end of file
diff --git a/util/contact.lua b/util/contact.lua
new file mode 100644
index 0000000..ff7c9c5
--- /dev/null
+++ b/util/contact.lua
@@ -0,0 +1,73 @@
+
+function mail.compile_contact_list(name, selected, playernames)
+	-- TODO: refactor this - not just compiles *a* list, but *the* list for the contacts screen (too inflexible)
+	local formspec = {}
+	local contacts = mail.get_contacts(name)
+
+	if playernames == nil then
+		local length = 0
+		for k, contact, i, l in mail.pairsByKeys(contacts) do
+			if i == 1 then length = l end
+			formspec[#formspec + 1] = ","
+			formspec[#formspec + 1] = ","
+			formspec[#formspec + 1] = minetest.formspec_escape(contact.name)
+			formspec[#formspec + 1] = ","
+			local note = contact.note
+			-- display an ellipsis if the note spans multiple lines
+			local idx = string.find(note, '\n')
+			if idx ~= nil then
+				note = string.sub(note, 1, idx-1) .. ' ...'
+			end
+			formspec[#formspec + 1] = minetest.formspec_escape(note)
+			if type(selected) == "string" then
+				if string.lower(selected) == k then
+					selected = i
+				end
+			end
+		end
+		if length > 0 then
+			if selected and type(selected) == "number" then
+				formspec[#formspec + 1] = ";"
+				formspec[#formspec + 1] = tostring(selected + 1)
+			end
+			formspec[#formspec + 1] = "]"
+		else
+			formspec[#formspec + 1] = "]label[2,4.5;No contacts]"
+		end
+	else
+		if type(playernames) == "string" then
+			playernames = mail.parse_player_list(playernames)
+		end
+		for i,c in ipairs(playernames) do
+			formspec[#formspec + 1] = ","
+			formspec[#formspec + 1] = ","
+			formspec[#formspec + 1] = minetest.formspec_escape(c)
+			formspec[#formspec + 1] = ","
+			if contacts[string.lower(c)] == nil then
+				formspec[#formspec + 1] = ""
+			else
+				local note = contacts[string.lower(c)].note
+				-- display an ellipsis if the note spans multiple lines
+				local idx = string.find(note, '\n')
+				if idx ~= nil then
+					note = string.sub(note, 1, idx-1) .. ' ...'
+				end
+				formspec[#formspec + 1] = minetest.formspec_escape(note)
+			end
+			if not selected then
+				if type(selected) == "string" then
+					if string.lower(selected) == string.lower(c) then
+						selected = i
+					end
+				end
+			end
+		end
+		if #playernames > 0 and selected and type(selected) == "number" then
+			formspec[#formspec + 1] = ";"
+			formspec[#formspec + 1] = tostring(selected + 1)
+		end
+		formspec[#formspec + 1] = "]"
+	end
+	return table.concat(formspec, "")
+
+end
\ No newline at end of file