diff --git a/README.md b/README.md
index eec6ce0..642aceb 100644
--- a/README.md
+++ b/README.md
@@ -74,31 +74,31 @@ docker run --name pgpool2_exporter \
 
 name | Pgpool-II Version | Description
 :---|:---|:---
-pgpool2_frontend_total | Pgpool-II 3.6+ | Number of total child processes
-pgpool2_frontend_used | Pgpool-II 3.6+ | Number of used child processes
-pgpool2_pool_nodes_status | Pgpool-II 3.6+ | Backend node Status (1 for up or waiting, 0 for down or unused)
-pgpool2_pool_nodes_replication_delay | Pgpool-II 3.6+ | Replication delay
-pgpool2_pool_nodes_select_cnt | Pgpool-II 3.6+ | SELECT query counts issued to each backend
-pgpool2_pool_cache_cache_hit_ratio | Pgpool-II 3.6+ | Query cache hit ratio
-pgpool2_pool_cache_num_cache_entries | Pgpool-II 3.6+ | Number of used cache entries
-pgpool2_pool_cache_num_hash_entries | Pgpool-II 3.6+ | Number of total hash entries
-pgpool2_pool_cache_used_hash_entries | Pgpool-II 3.6+ | Number of used hash entries
-pgpool2_pool_backend_stats_select_cnt | Pgpool-II 4.2+ | | SELECT statement counts issued to each backend
-pgpool2_pool_backend_stats_insert_cnt | Pgpool-II 4.2+ | | INSERT statement counts issued to each backend
-pgpool2_pool_backend_stats_update_cnt | Pgpool-II 4.2+ | | UPDATE statement counts issued to each backend
-pgpool2_pool_backend_stats_delete_cnt | Pgpool-II 4.2+ | | DELETE statement counts issued to each backend
-pgpool2_pool_backend_stats_ddl_cnt | Pgpool-II 4.2+ | | DDL statement counts issued to each backend
-pgpool2_pool_backend_stats_other_cnt | Pgpool-II 4.2+ | | other statement counts issued to each backend
-pgpool2_pool_backend_stats_panic_cnt | Pgpool-II 4.2+ | | Panic message counts returned from backend
-pgpool2_pool_backend_stats_fatal_cnt | Pgpool-II 4.2+ | | Fatal message counts returned from backend
-pgpool2_pool_backend_stats_error_cnt | Pgpool-II 4.2+ | | Error message counts returned from backend
-pgpool2_pool_health_check_stats_total_count | Pgpool-II 4.2+ | | Number of health check count in total
-pgpool2_pool_health_check_stats_success_count | Pgpool-II 4.2+ | | Number of successful health check count in total
-pgpool2_pool_health_check_stats_fail_count | Pgpool-II 4.2+ | | Number of failed health check count in total
-pgpool2_pool_health_check_stats_skip_count | Pgpool-II 4.2+ | | Number of skipped health check count in total
-pgpool2_pool_health_check_stats_retry_count | Pgpool-II 4.2+ | | Number of retried health check count in total
-pgpool2_pool_health_check_stats_average_retry_count | Pgpool-II 4.2+ | | Number of average retried health check count in a health check session
-pgpool2_pool_health_check_stats_max_retry_count | Pgpool-II 4.2+ | | Number of maximum retried health check count in a health check session
-pgpool2_pool_health_check_stats_max_duration | Pgpool-II 4.2+ | | Maximum health check duration in Millie seconds
-pgpool2_pool_health_check_stats_min_duration | Pgpool-II 4.2+ | | Minimum health check duration in Millie seconds
-pgpool2_pool_health_check_stats_average_duration | Pgpool-II 4.2+ | | Average health check duration in Millie seconds
+pgpool2_frontend_total | 3.6+ | Number of total child processes
+pgpool2_frontend_used | 3.6+ | Number of used child processes
+pgpool2_pool_nodes_status | 3.6+ | Backend node Status (1 for up or waiting, 0 for down or unused)
+pgpool2_pool_nodes_replication_delay | 3.6+ | Replication delay
+pgpool2_pool_nodes_select_cnt | 3.6+ | SELECT query counts issued to each backend
+pgpool2_pool_cache_cache_hit_ratio | 3.6+ | Query cache hit ratio
+pgpool2_pool_cache_num_cache_entries | 3.6+ | Number of used cache entries
+pgpool2_pool_cache_num_hash_entries | 3.6+ | Number of total hash entries
+pgpool2_pool_cache_used_hash_entries | 3.6+ | Number of used hash entries
+pgpool2_pool_backend_stats_select_cnt | 4.2+ | SELECT statement counts issued to each backend
+pgpool2_pool_backend_stats_insert_cnt | 4.2+ | INSERT statement counts issued to each backend
+pgpool2_pool_backend_stats_update_cnt | 4.2+ | UPDATE statement counts issued to each backend
+pgpool2_pool_backend_stats_delete_cnt | 4.2+ | DELETE statement counts issued to each backend
+pgpool2_pool_backend_stats_ddl_cnt | 4.2+ | DDL statement counts issued to each backend
+pgpool2_pool_backend_stats_other_cnt | 4.2+ | other statement counts issued to each backend
+pgpool2_pool_backend_stats_panic_cnt | 4.2+ | Panic message counts returned from backend
+pgpool2_pool_backend_stats_fatal_cnt | 4.2+ | Fatal message counts returned from backend
+pgpool2_pool_backend_stats_error_cnt | 4.2+ | Error message counts returned from backend
+pgpool2_pool_health_check_stats_total_count | 4.2+ | Number of health check count in total
+pgpool2_pool_health_check_stats_success_count | 4.2+ | Number of successful health check count in total
+pgpool2_pool_health_check_stats_fail_count | 4.2+ | Number of failed health check count in total
+pgpool2_pool_health_check_stats_skip_count | 4.2+ | Number of skipped health check count in total
+pgpool2_pool_health_check_stats_retry_count | 4.2+ | Number of retried health check count in total
+pgpool2_pool_health_check_stats_average_retry_count | 4.2+ | Number of average retried health check count in a health check session
+pgpool2_pool_health_check_stats_max_retry_count | 4.2+ | Number of maximum retried health check count in a health check session
+pgpool2_pool_health_check_stats_max_duration | 4.2+ | Maximum health check duration in Millie seconds
+pgpool2_pool_health_check_stats_min_duration | 4.2+ | Minimum health check duration in Millie seconds
+pgpool2_pool_health_check_stats_average_duration | 4.2+ | Average health check duration in Millie seconds