diff --git a/src/bpf_helpers.h b/src/bpf_helpers.h
index 963b106..44df982 100644
--- a/src/bpf_helpers.h
+++ b/src/bpf_helpers.h
@@ -133,7 +133,7 @@ struct bpf_map_def {
 	unsigned int value_size;
 	unsigned int max_entries;
 	unsigned int map_flags;
-};
+} __attribute__((deprecated("use BTF-defined maps in .maps section")));
 
 enum libbpf_pin_type {
 	LIBBPF_PIN_NONE,
diff --git a/src/libbpf.c b/src/libbpf.c
index fdb3536..fc6d530 100644
--- a/src/libbpf.c
+++ b/src/libbpf.c
@@ -1937,6 +1937,11 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 	if (obj->efile.maps_shndx < 0)
 		return 0;
 
+	if (libbpf_mode & LIBBPF_STRICT_MAP_DEFINITIONS) {
+		pr_warn("legacy map definitions in SEC(\"maps\") are not supported\n");
+		return -EOPNOTSUPP;
+	}
+
 	if (!symbols)
 		return -EINVAL;
 
@@ -1999,6 +2004,8 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 			return -LIBBPF_ERRNO__FORMAT;
 		}
 
+		pr_warn("map '%s' (legacy): legacy map definitions are deprecated, use BTF-defined maps instead\n", map_name);
+
 		if (ELF64_ST_BIND(sym->st_info) == STB_LOCAL) {
 			pr_warn("map '%s' (legacy): static maps are not supported\n", map_name);
 			return -ENOTSUP;
@@ -4190,6 +4197,7 @@ static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
 		return 0;
 
 	if (!bpf_map__is_internal(map)) {
+		pr_warn("Use of BPF_ANNOTATE_KV_PAIR is deprecated, use BTF-defined maps in .maps section instead\n");
 		ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size,
 					   def->value_size, &key_type_id,
 					   &value_type_id);
diff --git a/src/libbpf_legacy.h b/src/libbpf_legacy.h
index 79131f7..3c2b281 100644
--- a/src/libbpf_legacy.h
+++ b/src/libbpf_legacy.h
@@ -73,6 +73,11 @@ enum libbpf_strict_mode {
 	 * operation.
 	 */
 	LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK = 0x10,
+	/*
+	 * Error out on any SEC("maps") map definition, which are deprecated
+	 * in favor of BTF-defined map definitions in SEC(".maps").
+	 */
+	LIBBPF_STRICT_MAP_DEFINITIONS = 0x20,
 
 	__LIBBPF_STRICT_LAST,
 };