diff --git a/include/crm_internal.h b/include/crm_internal.h
index 6e79b2687c..4fbf6d282f 100644
--- a/include/crm_internal.h
+++ b/include/crm_internal.h
@@ -1,98 +1,105 @@
 /*
  * Copyright 2006-2021 the Pacemaker project contributors
  *
  * The version control history for this file may have further details.
  *
  * This source code is licensed under the GNU Lesser General Public License
  * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
  */
 
 #ifndef CRM_INTERNAL__H
 #  define CRM_INTERNAL__H
 
 #  ifndef PCMK__CONFIG_H
 #    define PCMK__CONFIG_H
 #    include <config.h>
 #  endif
 
 #  include <portability.h>
 
+/* Our minimum glib dependency is 2.42. Define that as both the minimum and
+ * maximum glib APIs that are allowed (i.e. APIs that were already deprecated
+ * in 2.42, and APIs introduced after 2.42, cannot be used by Pacemaker code).
+ */
+#define GLIB_VERSION_MIN_REQUIRED GLIB_VERSION_2_42
+#define GLIB_VERSION_MAX_ALLOWED GLIB_VERSION_2_42
+
 #  include <glib.h>
 #  include <stdbool.h>
 #  include <libxml/tree.h>
 
 /* Public API headers can guard including deprecated API headers with this
  * symbol, thus preventing internal code (which includes this header) from using
  * deprecated APIs, while still allowing external code to use them by default.
  */
 #define PCMK_ALLOW_DEPRECATED 0
 
 #  include <crm/lrmd.h>
 #  include <crm/common/logging.h>
 #  include <crm/common/logging_internal.h>
 #  include <crm/common/ipc_internal.h>
 #  include <crm/common/options_internal.h>
 #  include <crm/common/output_internal.h>
 #  include <crm/common/xml_internal.h>
 #  include <crm/common/internal.h>
 
 
 /*
  * XML attribute names used only by internal code
  */
 
 #define PCMK__XA_ATTR_DAMPENING         "attr_dampening"
 #define PCMK__XA_ATTR_FORCE             "attrd_is_force_write"
 #define PCMK__XA_ATTR_INTERVAL          "attr_clear_interval"
 #define PCMK__XA_ATTR_IS_PRIVATE        "attr_is_private"
 #define PCMK__XA_ATTR_IS_REMOTE         "attr_is_remote"
 #define PCMK__XA_ATTR_NAME              "attr_name"
 #define PCMK__XA_ATTR_NODE_ID           "attr_host_id"
 #define PCMK__XA_ATTR_NODE_NAME         "attr_host"
 #define PCMK__XA_ATTR_OPERATION         "attr_clear_operation"
 #define PCMK__XA_ATTR_PATTERN           "attr_regex"
 #define PCMK__XA_ATTR_RESOURCE          "attr_resource"
 #define PCMK__XA_ATTR_SECTION           "attr_section"
 #define PCMK__XA_ATTR_SET               "attr_set"
 #define PCMK__XA_ATTR_USER              "attr_user"
 #define PCMK__XA_ATTR_UUID              "attr_key"
 #define PCMK__XA_ATTR_VALUE             "attr_value"
 #define PCMK__XA_ATTR_VERSION           "attr_version"
 #define PCMK__XA_ATTR_WRITER            "attr_writer"
 #define PCMK__XA_MODE                   "mode"
 #define PCMK__XA_TASK                   "task"
 
 
 /*
  * IPC service names that are only used internally
  */
 
 #  define PCMK__SERVER_BASED_RO		"cib_ro"
 #  define PCMK__SERVER_BASED_RW		"cib_rw"
 #  define PCMK__SERVER_BASED_SHM		"cib_shm"
 
 /*
  * IPC commands that can be sent to Pacemaker daemons
  */
 
 #define PCMK__ATTRD_CMD_PEER_REMOVE     "peer-remove"
 #define PCMK__ATTRD_CMD_UPDATE          "update"
 #define PCMK__ATTRD_CMD_UPDATE_BOTH     "update-both"
 #define PCMK__ATTRD_CMD_UPDATE_DELAY    "update-delay"
 #define PCMK__ATTRD_CMD_QUERY           "query"
 #define PCMK__ATTRD_CMD_REFRESH         "refresh"
 #define PCMK__ATTRD_CMD_FLUSH           "flush"
 #define PCMK__ATTRD_CMD_SYNC            "sync"
 #define PCMK__ATTRD_CMD_SYNC_RESPONSE   "sync-response"
 #define PCMK__ATTRD_CMD_CLEAR_FAILURE   "clear-failure"
 
 #define PCMK__CONTROLD_CMD_NODES        "list-nodes"
 
 /*
  * Environment variables used by Pacemaker
  */
 
 #define PCMK__ENV_PHYSICAL_HOST         "physical_host"
 
 
 #endif                          /* CRM_INTERNAL__H */