diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index dd028a12a4..fe35da28f1 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -10587,6 +10587,7 @@ do_pg_start_backup(const char *backupidstr, bool fast, TimeLineID *starttli_p,
 						 backup_started_in_recovery ? "standby" : "master");
 		appendStringInfo(labelfile, "START TIME: %s\n", strfbuf);
 		appendStringInfo(labelfile, "LABEL: %s\n", backupidstr);
+		appendStringInfo(labelfile, "START TIMELINE: %u\n", starttli);
 
 		/*
 		 * Okay, write the file, or return its contents to caller.
@@ -11050,6 +11051,7 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive, TimeLineID *stoptli_p)
 		/* transfer remaining lines from label to history file */
 		fprintf(fp, "%s", remaining);
 		fprintf(fp, "STOP TIME: %s\n", strfbuf);
+		fprintf(fp, "STOP TIMELINE: %u\n", stoptli);
 		if (fflush(fp) || ferror(fp) || FreeFile(fp))
 			ereport(ERROR,
 					(errcode_for_file_access(),
@@ -11252,7 +11254,7 @@ read_backup_label(XLogRecPtr *checkPointLoc, bool *backupEndRequired,
 				  bool *backupFromStandby)
 {
 	char		startxlogfilename[MAXFNAMELEN];
-	TimeLineID	tli;
+	TimeLineID	tli1, tli2;
 	FILE	   *lfp;
 	char		ch;
 	char		backuptype[20];
@@ -11283,7 +11285,7 @@ read_backup_label(XLogRecPtr *checkPointLoc, bool *backupEndRequired,
 	 * format).
 	 */
 	if (fscanf(lfp, "START WAL LOCATION: %X/%X (file %08X%16s)%c",
-			   &hi, &lo, &tli, startxlogfilename, &ch) != 5 || ch != '\n')
+			   &hi, &lo, &tli1, startxlogfilename, &ch) != 5 || ch != '\n')
 		ereport(FATAL,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE)));
@@ -11312,6 +11314,20 @@ read_backup_label(XLogRecPtr *checkPointLoc, bool *backupEndRequired,
 			*backupFromStandby = true;
 	}
 
+	/*
+	 * START TIMELINE is new as of 11. Its parsing is not mandatory, still
+	 * use it as a sanity check if present.
+	 */
+	if (fscanf(lfp, "START TIMELINE: %u\n", &tli2) == 1)
+	{
+		if (tli1 != tli2)
+			ereport(FATAL,
+					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					 errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE),
+					 errdetail("Timeline ID parsed is %u, but expected %u",
+							   tli2, tli1)));
+	}
+
 	if (ferror(lfp) || FreeFile(lfp))
 		ereport(FATAL,
 				(errcode_for_file_access(),