diff --git a/RELNOTES.md b/RELNOTES.md
index 0587f1b..21f0801 100644
--- a/RELNOTES.md
+++ b/RELNOTES.md
@@ -1,6 +1,31 @@
 iperf3 Release Notes
 ====================
 
+iperf 3.9 2020-08-17
+--------------------
+
+* Notable user-visible changes
+
+  * A --timestamps flag has been added, which prepends a timestamp to
+    each output line.  An optional argument to this flag, which is a
+    format specification to strftime(3), allows for custom timestamp
+    formats (#909, #1028).
+
+  * A --server-bitrate-limit flag has been added as a server-side
+    command-line argument.  It allows a server to enforce a maximum
+    throughput rate; client connections that specify a higher bitrate
+    or exceed this bitrate during a test will be terminated.  The
+    bitrate is expressed in bits per second, with an optional trailing
+    slash and integer count that specifies an averaging interval over
+    which to enforce the limit (#999).
+
+  * A bug that caused increased CPU usage with the --bidir option has
+    been fixed (#1011).
+
+* Notable developer-visible changes
+
+  * Fixed various minor memory leaks (#1023).
+
 iperf 3.8.1 2020-06-10
 ----------------------
 
diff --git a/aclocal.m4 b/aclocal.m4
index 9310d8b..df70996 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1081,16 +1081,11 @@
       _lt_dar_allow_undefined='$wl-undefined ${wl}suppress' ;;
     darwin1.*)
       _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
-    darwin*) # darwin 5.x on
-      # if running on 10.5 or later, the deployment target defaults
-      # to the OS version, if on x86, and 10.4, the deployment
-      # target defaults to 10.4. Don't you love it?
-      case ${MACOSX_DEPLOYMENT_TARGET-10.0},$host in
-	10.0,*86*-darwin8*|10.0,*-darwin[[91]]*)
-	  _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
-	10.[[012]][[,.]]*)
+    darwin*)
+      case ${MACOSX_DEPLOYMENT_TARGET},$host in
+	10.[[012]],*|,*powerpc*)
 	  _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
-	10.*)
+	*)
 	  _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
       esac
     ;;
diff --git a/configure b/configure
index 82ec447..ee03ab2 100755
--- a/configure
+++ b/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for iperf 3.8.1.
+# Generated by GNU Autoconf 2.69 for iperf 3.9.
 #
 # Report bugs to <https://github.com/esnet/iperf>.
 #
@@ -590,8 +590,8 @@
 # Identity of this package.
 PACKAGE_NAME='iperf'
 PACKAGE_TARNAME='iperf'
-PACKAGE_VERSION='3.8.1'
-PACKAGE_STRING='iperf 3.8.1'
+PACKAGE_VERSION='3.9'
+PACKAGE_STRING='iperf 3.9'
 PACKAGE_BUGREPORT='https://github.com/esnet/iperf'
 PACKAGE_URL='https://software.es.net/iperf/'
 
@@ -1328,7 +1328,7 @@
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures iperf 3.8.1 to adapt to many kinds of systems.
+\`configure' configures iperf 3.9 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1398,7 +1398,7 @@
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of iperf 3.8.1:";;
+     short | recursive ) echo "Configuration of iperf 3.9:";;
    esac
   cat <<\_ACEOF
 
@@ -1516,7 +1516,7 @@
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-iperf configure 3.8.1
+iperf configure 3.9
 generated by GNU Autoconf 2.69
 
 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -1885,7 +1885,7 @@
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by iperf $as_me 3.8.1, which was
+It was created by iperf $as_me 3.9, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   $ $0 $@
@@ -2841,7 +2841,7 @@
 
 # Define the identity of the package.
  PACKAGE='iperf'
- VERSION='3.8.1'
+ VERSION='3.9'
 
 
 cat >>confdefs.h <<_ACEOF
@@ -7436,16 +7436,11 @@
       _lt_dar_allow_undefined='$wl-undefined ${wl}suppress' ;;
     darwin1.*)
       _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
-    darwin*) # darwin 5.x on
-      # if running on 10.5 or later, the deployment target defaults
-      # to the OS version, if on x86, and 10.4, the deployment
-      # target defaults to 10.4. Don't you love it?
-      case ${MACOSX_DEPLOYMENT_TARGET-10.0},$host in
-	10.0,*86*-darwin8*|10.0,*-darwin[91]*)
-	  _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
-	10.[012][,.]*)
+    darwin*)
+      case ${MACOSX_DEPLOYMENT_TARGET},$host in
+	10.[012],*|,*powerpc*)
 	  _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
-	10.*)
+	*)
 	  _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
       esac
     ;;
@@ -14572,7 +14567,7 @@
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by iperf $as_me 3.8.1, which was
+This file was extended by iperf $as_me 3.9, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -14639,7 +14634,7 @@
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-iperf config.status 3.8.1
+iperf config.status 3.9
 configured by $0, generated by GNU Autoconf 2.69,
   with options \\"\$ac_cs_config\\"
 
diff --git a/configure.ac b/configure.ac
index b2656e7..939cf0a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -24,7 +24,7 @@
 # file for complete information.
 
 # Initialize the autoconf system for the specified tool, version and mailing list
-AC_INIT(iperf, 3.8.1, https://github.com/esnet/iperf, iperf, https://software.es.net/iperf/)
+AC_INIT(iperf, 3.9, https://github.com/esnet/iperf, iperf, https://software.es.net/iperf/)
 m4_include([config/ax_check_openssl.m4])
 m4_include([config/iperf_config_static_bin.m4])
 AC_LANG(C)