diff --git a/CHANGES b/CHANGES
index 12bf25c2ee..176818a157 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+4550.	[cleanup]	Increased the number of available master file
+			output style flags from 32 to 64. [RT #44043]
+
 	--- 9.9.10b1 released ---
 
 4543.	[bug]		dns_client_startupdate now delays sending the update
diff --git a/lib/dns/include/dns/masterdump.h b/lib/dns/include/dns/masterdump.h
index 092c61b974..52311ca6bc 100644
--- a/lib/dns/include/dns/masterdump.h
+++ b/lib/dns/include/dns/masterdump.h
@@ -49,7 +49,7 @@ typedef struct dns_master_style dns_master_style_t;
  */
 
 /*% Omit the owner name when possible. */
-#define	DNS_STYLEFLAG_OMIT_OWNER        0x00010000U
+#define	DNS_STYLEFLAG_OMIT_OWNER        0x000010000ULL
 
 /*%
  * Omit the TTL when possible.  If DNS_STYLEFLAG_TTL is
@@ -67,38 +67,38 @@ typedef struct dns_master_style dns_master_style_t;
  * versions of BIND which use the SOA MINTTL as a
  * default TTL value.
  */
-#define	DNS_STYLEFLAG_OMIT_TTL		0x00020000U
+#define	DNS_STYLEFLAG_OMIT_TTL		0x000020000ULL
 
 /*% Omit the class when possible. */
-#define	DNS_STYLEFLAG_OMIT_CLASS	0x00040000U
+#define	DNS_STYLEFLAG_OMIT_CLASS	0x000040000ULL
 
 /*% Output $TTL directives. */
-#define	DNS_STYLEFLAG_TTL		0x00080000U
+#define	DNS_STYLEFLAG_TTL		0x000080000ULL
 
 /*%
  * Output $ORIGIN directives and print owner names relative to
  * the origin when possible.
  */
-#define	DNS_STYLEFLAG_REL_OWNER		0x00100000U
+#define	DNS_STYLEFLAG_REL_OWNER		0x000100000ULL
 
 /*% Print domain names in RR data in relative form when possible.
    For this to take effect, DNS_STYLEFLAG_REL_OWNER must also be set. */
-#define	DNS_STYLEFLAG_REL_DATA		0x00200000U
+#define	DNS_STYLEFLAG_REL_DATA		0x000200000ULL
 
 /*% Print the trust level of each rdataset. */
-#define	DNS_STYLEFLAG_TRUST		0x00400000U
+#define	DNS_STYLEFLAG_TRUST		0x000400000ULL
 
 /*% Print negative caching entries. */
-#define	DNS_STYLEFLAG_NCACHE		0x00800000U
+#define	DNS_STYLEFLAG_NCACHE		0x000800000ULL
 
 /*% Never print the TTL. */
-#define	DNS_STYLEFLAG_NO_TTL		0x01000000U
+#define	DNS_STYLEFLAG_NO_TTL		0x001000000ULL
 
 /*% Never print the CLASS. */
-#define	DNS_STYLEFLAG_NO_CLASS		0x02000000U
+#define	DNS_STYLEFLAG_NO_CLASS		0x002000000ULL
 
 /*% Report re-signing time. */
-#define	DNS_STYLEFLAG_RESIGN		0x04000000U
+#define	DNS_STYLEFLAG_RESIGN		0x004000000ULL
 
 ISC_LANG_BEGINDECLS
 
diff --git a/lib/dns/include/dns/rdata.h b/lib/dns/include/dns/rdata.h
index b9531a5792..7f9c76b96e 100644
--- a/lib/dns/include/dns/rdata.h
+++ b/lib/dns/include/dns/rdata.h
@@ -15,8 +15,6 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: rdata.h,v 1.80 2011/03/20 02:31:53 marka Exp $ */
-
 #ifndef DNS_RDATA_H
 #define DNS_RDATA_H 1
 
@@ -165,14 +163,17 @@ struct dns_rdata {
 
 /*% Split the rdata into multiple lines to try to keep it
  within the "width". */
-#define DNS_STYLEFLAG_MULTILINE		0x00000001U
+#define DNS_STYLEFLAG_MULTILINE		0x00000001ULL
 
 /*% Output explanatory comments. */
-#define DNS_STYLEFLAG_COMMENT		0x00000002U
-#define DNS_STYLEFLAG_RRCOMMENT		0x00000004U
+#define DNS_STYLEFLAG_COMMENT		0x00000002ULL
+#define DNS_STYLEFLAG_RRCOMMENT		0x00000004ULL
 
 /*% Output KEYDATA in human readable format. */
-#define DNS_STYLEFLAG_KEYDATA		0x00000008U
+#define DNS_STYLEFLAG_KEYDATA		0x00000008ULL
+
+/*% Output textual RR type and RDATA in RFC 3597 unknown format */
+#define DNS_STYLEFLAG_UNKNOWNFORMAT	0x00000010ULL
 
 #define DNS_RDATA_DOWNCASE		DNS_NAME_DOWNCASE
 #define DNS_RDATA_CHECKNAMES		DNS_NAME_CHECKNAMES
diff --git a/lib/dns/include/dns/types.h b/lib/dns/include/dns/types.h
index 54194aa2a9..8028f8b2a7 100644
--- a/lib/dns/include/dns/types.h
+++ b/lib/dns/include/dns/types.h
@@ -88,6 +88,7 @@ typedef isc_uint16_t				dns_keytag_t;
 typedef struct dns_loadctx			dns_loadctx_t;
 typedef struct dns_loadmgr			dns_loadmgr_t;
 typedef struct dns_masterrawheader		dns_masterrawheader_t;
+typedef isc_uint64_t				dns_masterstyle_flags_t;
 typedef struct dns_message			dns_message_t;
 typedef isc_uint16_t				dns_messageid_t;
 typedef isc_region_t				dns_label_t;
diff --git a/lib/dns/masterdump.c b/lib/dns/masterdump.c
index cfd2d13d7d..7ea2e326fc 100644
--- a/lib/dns/masterdump.c
+++ b/lib/dns/masterdump.c
@@ -32,6 +32,7 @@
 #include <isc/string.h>
 #include <isc/task.h>
 #include <isc/time.h>
+#include <isc/types.h>
 #include <isc/util.h>
 
 #include <dns/db.h>
@@ -67,7 +68,7 @@
 	} while (0)
 
 struct dns_master_style {
-	unsigned int flags;		/* DNS_STYLEFLAG_* */
+	dns_masterstyle_flags_t flags;		/* DNS_STYLEFLAG_* */
 	unsigned int ttl_column;
 	unsigned int class_column;
 	unsigned int type_column;