diff --git a/node.go b/node.go
index 6b79769..e3a61d5 100644
--- a/node.go
+++ b/node.go
@@ -54,7 +54,6 @@ type Node struct {
 	DeletedSeq       sql.NullInt64 `db:"deleted_seq"`
 	Content          string
 	ContentEncrypted string `db:"content_encrypted" json:"-"`
-	Markdown         bool
 }
 
 func NodeTree(userID, offset int, synced uint64) (nodes []TreeNode, maxSeq uint64, moreRowsExist bool, err error) { // {{{
@@ -75,7 +74,7 @@ func NodeTree(userID, offset int, synced uint64) (nodes []TreeNode, maxSeq uint6
 			public.node
 		WHERE
 			user_id = $1 AND 
-			NOT history AND (
+			(
 				created_seq > $4 OR
 				updated_seq > $4 OR
 				deleted_seq > $4
@@ -132,14 +131,13 @@ func Nodes(userID, offset int, synced uint64, clientUUID string) (nodes []Node,
 			updated_seq,
 			deleted_seq,
 			content,
-			content_encrypted,
-			markdown
+			content_encrypted
 		FROM
 			public.node
 		WHERE
 			user_id = $1 AND
 			client != $5::uuid AND
-			NOT history AND (
+			(
 				created_seq > $4 OR
 				updated_seq > $4 OR
 				deleted_seq > $4
@@ -192,7 +190,7 @@ func NodesCount(userID int, synced uint64, clientUUID string) (count int, err er
 		WHERE
 			user_id = $1 AND
 			client != $3 AND
-			NOT history AND (
+			(
 				created_seq > $2 OR
 				updated_seq > $2 OR
 				deleted_seq > $2
diff --git a/sql/00005.sql b/sql/00005.sql
new file mode 100644
index 0000000..b272085
--- /dev/null
+++ b/sql/00005.sql
@@ -0,0 +1,129 @@
+-- Some cleanup of old columns not used anymore.
+DROP INDEX public.node_history_client_idx;
+ALTER TABLE public.node_history DROP COLUMN client_sequence;
+
+ALTER TABLE public.node DROP COLUMN markdown;
+DROP INDEX public.node_history_idx;
+ALTER TABLE public.node DROP COLUMN history;
+ALTER TABLE public.node DROP COLUMN client_sequence;
+
+
+
+CREATE OR REPLACE PROCEDURE public.add_nodes(IN p_user_id integer, IN p_client_uuid uuid, IN p_nodes jsonb)
+ LANGUAGE plpgsql
+AS $procedure$
+
+DECLARE
+	node_data         jsonb;
+	node_updated      timestamptz;
+	db_updated        timestamptz;
+	db_uuid           uuid;
+	db_client         uuid;
+	db_history_uuid   uuid;
+	node_uuid         uuid;
+	node_parent_uuid  uuid;
+	node_history_uuid uuid;
+
+BEGIN
+	FOR node_data IN SELECT * FROM jsonb_array_elements(p_nodes)
+	LOOP
+		node_uuid         = (node_data->>'UUID')::uuid;
+		node_history_uuid = (node_data->>'HistoryUUID')::uuid;
+		node_updated      = (node_data->>'Updated')::timestamptz;
+
+
+
+		-- Frontend is using an all-zero UUID to define the root node.
+		-- Database is using NULL.
+		IF node_data->>'ParentUUID' = '00000000-0000-0000-0000-000000000000' OR node_data->>'ParentUUID' = '' THEN
+			node_parent_uuid = NULL;
+		ELSE
+			node_parent_uuid = (node_data->>'ParentUUID')::uuid;
+		END IF;
+
+
+
+		-- Every jode has a new history UUID to keep the history entry uniquely identifiable
+		-- across clients. A history entry could potentially be sent again, but should be
+		-- safe to ignore as every change to a node should have a new history UUID.
+		--
+		-- The current node is also stored as history.
+		INSERT INTO node_history(
+			user_id, "uuid", "history_uuid", parents, created, updated,
+			"name", "content", "content_encrypted",
+			client
+		)
+		VALUES(
+			p_user_id, -- combined key
+			node_uuid, -- combined key
+			node_history_uuid, -- combined key
+			(jsonb_populate_record(null::json_ancestor_array, node_data))."Ancestors",
+			COALESCE((node_data->>'Created')::timestamptz, NOW()),
+			COALESCE((node_data->>'Updated')::timestamptz, NOW()),
+			(node_data->>'Name')::varchar,
+			(node_data->>'Content')::text,
+			'', /* content_encrypted */
+			p_client_uuid
+		)
+		ON CONFLICT ("user_id", "uuid", "history_uuid")
+		DO NOTHING;
+
+
+
+		-- Retrieve the current modified timestamp for this node from the database.
+		SELECT
+			uuid, updated, client
+		INTO
+			db_uuid, db_updated, db_client
+		FROM public."node"
+		WHERE
+			user_id = p_user_id AND
+			uuid::uuid = node_uuid::uuid;
+
+
+
+		-- Is the node not in database? It needs to be created.
+		IF db_uuid IS NULL THEN
+			RAISE NOTICE '01 New node %', node_uuid;
+
+			INSERT INTO public."node" (
+				user_id, "uuid", parent_uuid, created, updated,
+				"name", "content", "content_encrypted",
+				client
+			)
+			VALUES(
+				p_user_id,
+				node_uuid,
+				node_parent_uuid,
+				COALESCE((node_data->>'Created')::timestamptz, NOW()),
+				COALESCE((node_data->>'Updated')::timestamptz, NOW()),
+				(node_data->>'Name')::varchar,
+				(node_data->>'Content')::text,
+				'', /* content_encrypted */
+				p_client_uuid
+			);
+
+			CONTINUE;
+
+		END IF;
+
+
+
+		-- Update the public node as well if it was older than incoming node.
+		IF node_updated > db_updated THEN
+			UPDATE public."node"
+			SET
+				updated = (node_data->>'Updated')::timestamptz,
+				updated_seq = nextval('node_updates'),
+				name = (node_data->>'Name')::varchar,
+				content = (node_data->>'Content')::text,
+				client = p_client_uuid
+			WHERE
+				user_id = p_user_id AND
+				uuid::uuid = node_uuid::uuid;
+		END IF;
+
+	END LOOP;
+END
+$procedure$
+;