diff --git a/configure b/configure
index 4ecd2e1922..b8995ad547 100755
--- a/configure
+++ b/configure
@@ -16807,7 +16807,7 @@ _ACEOF
 # awk -F is a regex on some platforms, and not on others, so make "." a tab
 PG_VERSION_NUM="`echo "$PACKAGE_VERSION" | sed 's/[A-Za-z].*$//' |
 tr '.' '	' |
-$AWK '{printf "%d%02d%02d", $1, $2, (NF >= 3) ? $3 : 0}'`"
+$AWK '{printf "%d%04d", $1, $2}'`"
 
 cat >>confdefs.h <<_ACEOF
 #define PG_VERSION_NUM $PG_VERSION_NUM
diff --git a/configure.in b/configure.in
index cea7fd0755..2b209d80ab 100644
--- a/configure.in
+++ b/configure.in
@@ -2181,7 +2181,7 @@ AC_DEFINE_UNQUOTED(PG_VERSION_STR,
 # awk -F is a regex on some platforms, and not on others, so make "." a tab
 [PG_VERSION_NUM="`echo "$PACKAGE_VERSION" | sed 's/[A-Za-z].*$//' |
 tr '.' '	' |
-$AWK '{printf "%d%02d%02d", $1, $2, (NF >= 3) ? $3 : 0}'`"]
+$AWK '{printf "%d%04d", $1, $2}'`"]
 AC_DEFINE_UNQUOTED(PG_VERSION_NUM, $PG_VERSION_NUM, [PostgreSQL version as a number])
 AC_SUBST(PG_VERSION_NUM)
 
diff --git a/src/bin/pg_upgrade/exec.c b/src/bin/pg_upgrade/exec.c
index 1cf64e1a45..59ddc16d6b 100644
--- a/src/bin/pg_upgrade/exec.c
+++ b/src/bin/pg_upgrade/exec.c
@@ -26,7 +26,7 @@ static int	win32_check_directory_write_permissions(void);
 /*
  * get_bin_version
  *
- *	Fetch versions of binaries for cluster.
+ *	Fetch major version of binaries for cluster.
  */
 static void
 get_bin_version(ClusterInfo *cluster)
@@ -34,8 +34,8 @@ get_bin_version(ClusterInfo *cluster)
 	char		cmd[MAXPGPATH],
 				cmd_output[MAX_STRING];
 	FILE	   *output;
-	int			pre_dot = 0,
-				post_dot = 0;
+	int			v1 = 0,
+				v2 = 0;
 
 	snprintf(cmd, sizeof(cmd), "\"%s/pg_ctl\" --version", cluster->bindir);
 
@@ -46,14 +46,19 @@ get_bin_version(ClusterInfo *cluster)
 
 	pclose(output);
 
-	/* Remove trailing newline */
-	if (strchr(cmd_output, '\n') != NULL)
-		*strchr(cmd_output, '\n') = '\0';
-
-	if (sscanf(cmd_output, "%*s %*s %d.%d", &pre_dot, &post_dot) < 1)
+	if (sscanf(cmd_output, "%*s %*s %d.%d", &v1, &v2) < 1)
 		pg_fatal("could not get pg_ctl version output from %s\n", cmd);
 
-	cluster->bin_version = (pre_dot * 100 + post_dot) * 100;
+	if (v1 < 10)
+	{
+		/* old style, e.g. 9.6.1 */
+		cluster->bin_version = v1 * 10000 + v2 * 100;
+	}
+	else
+	{
+		/* new style, e.g. 10.1 */
+		cluster->bin_version = v1 * 10000;
+	}
 }
 
 
diff --git a/src/bin/pg_upgrade/server.c b/src/bin/pg_upgrade/server.c
index 3e3323a6e8..a91f18916c 100644
--- a/src/bin/pg_upgrade/server.c
+++ b/src/bin/pg_upgrade/server.c
@@ -156,8 +156,8 @@ get_major_server_version(ClusterInfo *cluster)
 {
 	FILE	   *version_fd;
 	char		ver_filename[MAXPGPATH];
-	int			integer_version = 0;
-	int			fractional_version = 0;
+	int			v1 = 0,
+				v2 = 0;
 
 	snprintf(ver_filename, sizeof(ver_filename), "%s/PG_VERSION",
 			 cluster->pgdata);
@@ -165,13 +165,21 @@ get_major_server_version(ClusterInfo *cluster)
 		pg_fatal("could not open version file: %s\n", ver_filename);
 
 	if (fscanf(version_fd, "%63s", cluster->major_version_str) == 0 ||
-		sscanf(cluster->major_version_str, "%d.%d", &integer_version,
-			   &fractional_version) < 1)
+		sscanf(cluster->major_version_str, "%d.%d", &v1, &v2) < 1)
 		pg_fatal("could not parse PG_VERSION file from %s\n", cluster->pgdata);
 
 	fclose(version_fd);
 
-	return (100 * integer_version + fractional_version) * 100;
+	if (v1 < 10)
+	{
+		/* old style, e.g. 9.6.1 */
+		return v1 * 10000 + v2 * 100;
+	}
+	else
+	{
+		/* new style, e.g. 10.1 */
+		return v1 * 10000;
+	}
 }