diff --git a/Makefile.defs b/Makefile.defs
index 95e9815c..49814477 100644
--- a/Makefile.defs
+++ b/Makefile.defs
@@ -166,6 +166,7 @@ CXX = g++
 CC = gcc
 LD = $(CC)
 
+CXXFLAGS += -std=c++20
 CXXFLAGS += -Wall -Wno-reorder -Wno-unused -fPIC -g $(EXTRA_CXXFLAGS) 
 CFLAGS   += -Wall -fPIC -g $(EXTRA_CFLAGS)
 
diff --git a/apps/xmlrpc2di/xmlrpc++/Makefile b/apps/xmlrpc2di/xmlrpc++/Makefile
index b2b1e02f..04bc9d24 100644
--- a/apps/xmlrpc2di/xmlrpc++/Makefile
+++ b/apps/xmlrpc2di/xmlrpc++/Makefile
@@ -6,7 +6,7 @@ CPPFLAGS	+= -I$(SRC) -fPIC -Wno-deprecated-declarations
 DEBUG		= -g
 OPTIMIZE	= -O2
 GCCWARN		= -Wall #-Wstrict-prototypes
-CXXFLAGS	= $(DEBUG) $(GCCWARN) $(OPTIMIZE) $(INCLUDES)
+CXXFLAGS	= -std=c++20 $(DEBUG) $(GCCWARN) $(OPTIMIZE) $(INCLUDES)
 ARFLAGS		= rvs
 VERSION		= 0.8
 
diff --git a/apps/xmlrpc2di/xmlrpc++/test/Makefile b/apps/xmlrpc2di/xmlrpc++/test/Makefile
index 8067ee38..a853a529 100644
--- a/apps/xmlrpc2di/xmlrpc++/test/Makefile
+++ b/apps/xmlrpc2di/xmlrpc++/test/Makefile
@@ -5,7 +5,7 @@ CPPFLAGS	= -I$(SRC)
 DEBUG		= -g
 #OPTIMIZE	= -O2
 GCCWARN		= -Wall -Wstrict-prototypes
-CXXFLAGS	= $(DEBUG) $(GCCWARN) $(OPTIMIZE) $(INCLUDES)
+CXXFLAGS	= std=c++20 $(DEBUG) $(GCCWARN) $(OPTIMIZE) $(INCLUDES)
 
 LIB		= ../libXmlRpc.a -lssl
 
diff --git a/debian/rules b/debian/rules
index 313472ea..f01d21e1 100755
--- a/debian/rules
+++ b/debian/rules
@@ -9,7 +9,7 @@ EXCLUDED_MODULES=conf_auth examples/db_announce fast_ack gateway ivr mailbox mp3
 EXCLUDED_DSM_MODULES=mod_aws mod_py
 EXCLUDED_DSM_PY_MODULES=mod_aws mod_py
 
-CPPFLAGS += -DHAVE_XMLRPCPP_SSL -std=c++20
+CPPFLAGS += -DHAVE_XMLRPCPP_SSL
 
 export USE_SPANDSP=yes LONG_DEBUG_MESSAGE=yes CPPFLAGS="$(CPPFLAGS)"