diff --git a/library/client/http_client/http_client.ecf b/library/client/http_client/http_client.ecf
index 0240a509..5aeb4acd 100644
--- a/library/client/http_client/http_client.ecf
+++ b/library/client/http_client/http_client.ecf
@@ -7,7 +7,7 @@
 			<exclude>/EIFGENs$</exclude>
 			<exclude>/.svn$</exclude>
 		</file_rule>
-		<option warning="true" full_class_checking="true" void_safety="none" syntax="standard">
+		<option warning="true" full_class_checking="true" void_safety="none" syntax="provisional">
 		</option>
 		<library name="base" location="$ISE_LIBRARY/library/base/base.ecf"/>
 		<library name="cURL" location="$ISE_LIBRARY/library/cURL/cURL.ecf"/>
diff --git a/library/server/ewsgi/specification/response/wgi_response_buffer.e b/library/server/ewsgi/specification/response/wgi_response_buffer.e
index 7cf4e9fa..b5b619fc 100644
--- a/library/server/ewsgi/specification/response/wgi_response_buffer.e
+++ b/library/server/ewsgi/specification/response/wgi_response_buffer.e
@@ -69,7 +69,7 @@ feature -- Status setting
 
 feature -- Header output operation
 
-	write_headers_string (a_headers: STRING)
+	write_headers_string (a_headers: READABLE_STRING_8)
 		require
 			status_set: status_is_set
 			header_not_committed: not header_committed
@@ -80,7 +80,7 @@ feature -- Header output operation
 			message_writable: message_writable
 		end
 
-	write_header (a_status_code: INTEGER; a_headers: detachable ARRAY [TUPLE [key: STRING; value: STRING]])
+	write_header (a_status_code: INTEGER; a_headers: detachable ARRAY [TUPLE [key: READABLE_STRING_8; value: READABLE_STRING_8]])
 			-- Send headers with status `a_status', and headers from `a_headers'
 		require
 			status_not_set: not status_is_set
@@ -94,21 +94,21 @@ feature -- Header output operation
 
 feature -- Output operation
 
-	write_string (s: STRING)
+	write_string (s: READABLE_STRING_8)
 			-- Send the string `s'
 		require
 			message_writable: message_writable
 		deferred
 		end
 
-	write_substring (s: STRING; a_begin_index, a_end_index: INTEGER)
+	write_substring (s: READABLE_STRING_8; a_begin_index, a_end_index: INTEGER)
 			-- Send the substring `s[a_begin_index:a_end_index]'
 		require
 			message_writable: message_writable
 		deferred
 		end
 
-	write_file_content (fn: STRING)
+	write_file_content (fn: READABLE_STRING_8)
 			-- Send the content of file `fn'
 		require
 			message_writable: message_writable
diff --git a/library/server/request/rest/src/uri/rest_request_uri_routing_handler_i.e b/library/server/request/rest/src/uri/rest_request_uri_routing_handler_i.e
index badbe29d..6fc843d4 100644
--- a/library/server/request/rest/src/uri/rest_request_uri_routing_handler_i.e
+++ b/library/server/request/rest/src/uri/rest_request_uri_routing_handler_i.e
@@ -25,7 +25,14 @@ create
 
 feature -- Status report
 
-	authentication_required: BOOLEAN
+	authentication_required (req: WGI_REQUEST): BOOLEAN
+		do
+			Result := internal_authentication_required
+		end
+
+feature {NONE} -- Implementation
+
+	internal_authentication_required: BOOLEAN
 
 feature -- Execution
 
diff --git a/library/server/request/rest/tests/src/app/app_account_verify_credential.e b/library/server/request/rest/tests/src/app/app_account_verify_credential.e
index 17efb516..3161dff7 100644
--- a/library/server/request/rest/tests/src/app/app_account_verify_credential.e
+++ b/library/server/request/rest/tests/src/app/app_account_verify_credential.e
@@ -63,9 +63,9 @@ feature -- Execution
 		do
 			content_type_supported := <<{HTTP_CONSTANTS}.json_app, {HTTP_CONSTANTS}.xml_text, {HTTP_CONSTANTS}.plain_text>>
 			l_format_id := ctx.request_format_id ("format", content_type_supported)
-			if ctx.authenticated then
+			if authenticated (ctx) then
 				l_full := attached ctx.query_parameter ("details") as v and then v.is_case_insensitive_equal ("true")
-				if attached ctx.authenticated_identifier as log then
+				if attached authenticated_identifier (ctx) as log then
 					l_login := log.as_string_8
 
 					create h.make
diff --git a/library/server/request/rest/tests/src/app/app_test.e b/library/server/request/rest/tests/src/app/app_test.e
index f642977a..031044c5 100644
--- a/library/server/request/rest/tests/src/app/app_test.e
+++ b/library/server/request/rest/tests/src/app/app_test.e
@@ -70,7 +70,7 @@ feature -- Execution
 --					if attached ctx.http_authorization_login_password as t then
 --						s.append_string ("Check login=" + t.login + "<br/>%N")
 --					end
-					if ctx.authenticated and then attached ctx.authenticated_identifier as l_login then
+					if authenticated (ctx) and then attached authenticated_identifier (ctx) as l_login then
 						s.append_string ("Authenticated: login=" + l_login.as_string_8 + "<br/>%N")
 					end
 				end
diff --git a/library/server/request/rest/tests/src/handler/app_request_agent_handler.e b/library/server/request/rest/tests/src/handler/app_request_agent_handler.e
index a59ab7ab..49551d2a 100644
--- a/library/server/request/rest/tests/src/handler/app_request_agent_handler.e
+++ b/library/server/request/rest/tests/src/handler/app_request_agent_handler.e
@@ -14,6 +14,9 @@ inherit
 		end
 
 	REST_REQUEST_AGENT_HANDLER [APP_REQUEST_HANDLER_CONTEXT]
+		undefine
+			authenticated
+		end
 
 create
 	make
diff --git a/library/server/request/rest/tests/src/handler/app_request_handler.e b/library/server/request/rest/tests/src/handler/app_request_handler.e
index 01e78d9c..71214e66 100644
--- a/library/server/request/rest/tests/src/handler/app_request_handler.e
+++ b/library/server/request/rest/tests/src/handler/app_request_handler.e
@@ -8,6 +8,9 @@ deferred class
 
 inherit
 	REST_REQUEST_HANDLER [APP_REQUEST_HANDLER_CONTEXT]
+		redefine
+			authenticated
+		end
 
 	APP_REQUEST_HELPER
 
@@ -17,7 +20,7 @@ feature {NONE} -- Initialization
 			-- Initialize various attributes
 		do
 		end
-		
+
 feature {NONE} -- Implementation
 
 	wgi_value_iteration_to_string (cur: ITERATION_CURSOR [WGI_VALUE]; using_pre: BOOLEAN): STRING_8
@@ -38,6 +41,24 @@ feature {NONE} -- Implementation
 			end
 		end
 
+feature -- Auth
+
+	authenticated (ctx: APP_REQUEST_HANDLER_CONTEXT): BOOLEAN
+			-- Is authenticated?
+		do
+			--| To redefine if needed
+			if attached ctx.request.http_authorization as l_http_authorization then
+				Result := True
+			end
+		end
+
+	authenticated_identifier (ctx: APP_REQUEST_HANDLER_CONTEXT): detachable READABLE_STRING_32
+		do
+			if attached ctx.request.http_authorization as l_http_authorization then
+				Result := "foo" -- Implement it as you want
+			end
+		end
+
 feature -- Helpers
 
 	format_id (s: detachable STRING): INTEGER
diff --git a/library/server/request/rest/tests/src/handler/app_request_handler_context.e b/library/server/request/rest/tests/src/handler/app_request_handler_context.e
index 98bd12de..76b703a0 100644
--- a/library/server/request/rest/tests/src/handler/app_request_handler_context.e
+++ b/library/server/request/rest/tests/src/handler/app_request_handler_context.e
@@ -9,29 +9,10 @@ class
 
 inherit
 	REST_REQUEST_URI_TEMPLATE_HANDLER_CONTEXT
-		redefine
-			authenticated,
-			authenticated_identifier
-		end
 
 create
 	make
 
-feature -- Auth
-
-	authenticated: BOOLEAN
-		do
-			if attached request.http_authorization as l_http_auth then
-				Result := True
-			end
-		end
-
-	authenticated_identifier: detachable READABLE_STRING_32
-		do
-			if authenticated then
-				Result := "foo"
-			end
-		end
 
 feature -- Format
 
diff --git a/library/server/request/rest/tests/src/handler/app_request_routing_handler.e b/library/server/request/rest/tests/src/handler/app_request_routing_handler.e
index 63e0196f..f6db6ec1 100644
--- a/library/server/request/rest/tests/src/handler/app_request_routing_handler.e
+++ b/library/server/request/rest/tests/src/handler/app_request_routing_handler.e
@@ -10,12 +10,14 @@ class
 inherit
 	APP_REQUEST_HANDLER
 		undefine
-			execute,
-			pre_execute,
-			post_execute
+			execute
 		end
 
 	REST_REQUEST_URI_TEMPLATE_ROUTING_HANDLER_I [APP_REQUEST_HANDLER, APP_REQUEST_HANDLER_CONTEXT]
+		undefine
+			authenticated,
+			pre_execute,
+			post_execute
 		redefine
 			router
 		end
diff --git a/library/server/request/router/src/misc/routed_application_helper.e b/library/server/request/router/src/misc/routed_application_helper.e
index 0cce19bf..092511d2 100644
--- a/library/server/request/router/src/misc/routed_application_helper.e
+++ b/library/server/request/router/src/misc/routed_application_helper.e
@@ -14,31 +14,28 @@ feature -- Helper
 
 	execute_content_type_not_allowed (req: WGI_REQUEST; res: WGI_RESPONSE_BUFFER; a_content_types: detachable ARRAY [STRING]; a_uri_formats: detachable ARRAY [STRING])
 		local
-			s, uri_s: detachable STRING
+			accept_s, uri_s: detachable STRING
 			i, n: INTEGER
-			h: EWF_HEADER
 		do
-			create h.make
-			h.put_status ({HTTP_STATUS_CODE}.unsupported_media_type)
-			h.put_content_type_text_plain
-
 			if a_content_types /= Void then
-				create s.make (10)
+				create accept_s.make (10)
 				from
 					i := a_content_types.lower
 					n := a_content_types.upper
 				until
 					i > n
 				loop
-					s.append_string (a_content_types[i])
+					accept_s.append_string (a_content_types[i])
 					if i < n then
-						s.append_character (',')
-						s.append_character (' ')
+						accept_s.append_character (',')
+						accept_s.append_character (' ')
 					end
 					i := i + 1
 				end
-				h.put_header_key_value ("Accept", s)
+			else
+				accept_s := "*/*"
 			end
+
 			if a_uri_formats /= Void then
 				create uri_s.make (10)
 				from
@@ -56,9 +53,9 @@ feature -- Helper
 				end
 			end
 			res.set_status_code ({HTTP_STATUS_CODE}.unsupported_media_type)
-			res.write_headers_string (h.string)
-			if s /= Void then
-				res.write_string ("Unsupported request content-type, Accept: " + s + "%N")
+			res.write_header ({HTTP_STATUS_CODE}.unsupported_media_type, << ["Content-Type", "text/plain"], ["Accept", accept_s]>>)
+			if accept_s /= Void then
+				res.write_string ("Unsupported request content-type, Accept: " + accept_s + "%N")
 			end
 			if uri_s /= Void then
 				res.write_string ("Unsupported request format from the URI: " + uri_s + "%N")