diff --git a/CHANGELOG b/CHANGELOG
index e4599759c..2b7ae9ef2 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,17 +1,33 @@
 #Nmap Changelog ($Id$); -*-text-*-
 
-o [NSE][GH#2136][GH#2137] Rectify error "time result cannot be represented..."
-  in the AFP library. [Clément Notin]
-
-o [NSE][GH#1473] It is now possible to control whether the SNMP library uses
-  v1 (default) or v2c by setting script argument snmp.version. [nnposter]
- 
-o [NSE][GH#2128] MySQL library was not properly parsing server responses,
-  resulting in script crashes. [nnposter]
-
 o [NSE] Script mysql-audit now defaults to the bundled mysql-cis.audit for
   the audit rule base. [nnposter]
 
+o [NSE][GH#1473] It is now possible to control whether the SNMP library uses
+  v1 (default) or v2c by setting script argument snmp.version. [nnposter]
+
+Nmap 7.91 [2020-10-09]
+
+o [GH#2148][Zenmap] Fix a crash in the profile editor due to a missing import.
+
+o [GH#2139][Nsock][Windows] Demote the IOCP Nsock engine because of some known
+  issues that will take longer to resolve. The previous default "poll" engine
+  will be used instead.
+
+o [GH#2138][Nsock][Windows] Fix a crash in service scan due to a previously-unknown
+  error being returned from the IOCP Nsock engine. [Daniel Miller]
+
+o [NSE][GH#2136][GH#2137] Fix several places where Lua's os.time was being used
+  to represent dates prior to January 1, 1970, which fails on Windows. Notably,
+  NSE refused to run in UTC+X timezones with the error "time result cannot be
+  represented in this installation" [Clément Notin, nnposter, Daniel Miller]
+
+o [NSE][GH#2128] MySQL library was not properly parsing server responses,
+  resulting in script crashes. [nnposter]
+
+o [GH#2135] Silence the irrelevant warning, "Your ports include 'T:' but you
+  haven't specified any TCP scan type" when running nmap -sUV
+
 Nmap 7.90 [2020-10-03]
 
 o [Windows] Upgraded Npcap, our Windows packet capturing (and sending)
diff --git a/docs/nmap.usage.txt b/docs/nmap.usage.txt
index fadba069d..f553ad4b0 100644
--- a/docs/nmap.usage.txt
+++ b/docs/nmap.usage.txt
@@ -1,4 +1,4 @@
-Nmap 7.90SVN ( https://nmap.org )
+Nmap 7.91SVN ( https://nmap.org )
 Usage: nmap [Scan Type(s)] [Options] {target specification}
 TARGET SPECIFICATION:
   Can pass hostnames, IP addresses, networks, etc.
diff --git a/macosx/openssl.modules b/macosx/openssl.modules
index 1d67273a3..368ba7a7e 100644
--- a/macosx/openssl.modules
+++ b/macosx/openssl.modules
@@ -30,7 +30,7 @@
         makeargs='OPENSSL_LIBS="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a" LIBSSL="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a" ZLIB_LIBS="${JHBUILD_LIBDIR}/libz.a" LIBZ="${JHBUILD_LIBDIR}/libz.a"'
 	makeinstallargs='install OPENSSL_LIBS="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a" ZLIB_LIBS="${JHBUILD_LIBDIR}/libz.a"'
     >
-        <branch repo="nmap-local" module="nmap-7.90.tar.gz" version="7.90"/>
+        <branch repo="nmap-local" module="nmap-7.91.tar.gz" version="7.91"/>
         <dependencies>
             <dep package="openssl" />
         </dependencies>
@@ -42,7 +42,7 @@
         makeargs='build-ncat OPENSSL_LIBS="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a"'
         makeinstallargs='install-ncat OPENSSL_LIBS="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a"'
     >
-        <branch repo="nmap-local" module="nmap-7.90.tar.gz" version="7.90"/>
+        <branch repo="nmap-local" module="nmap-7.91.tar.gz" version="7.91"/>
         <dependencies>
             <dep package="openssl" />
         </dependencies>
@@ -54,7 +54,7 @@
         makeargs='build-nping OPENSSL_LIBS="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a"'
         makeinstallargs='install-nping OPENSSL_LIBS="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a"'
     >
-        <branch repo="nmap-local" module="nmap-7.90.tar.gz" version="7.90"/>
+        <branch repo="nmap-local" module="nmap-7.91.tar.gz" version="7.91"/>
         <dependencies>
             <dep package="openssl" />
         </dependencies>
@@ -66,7 +66,7 @@
         makeargs='OPENSSL_LIBS="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a" LIBSSL="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a" ZLIB_LIBS="${JHBUILD_LIBDIR}/libz.a" LIBZ="${JHBUILD_LIBDIR}/libz.a"'
 	makeinstallargs='install OPENSSL_LIBS="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a" ZLIB_LIBS="${JHBUILD_LIBDIR}/libz.a"'
     >
-        <branch repo="nmap-local" module="nmap-7.90.tar.gz" version="7.90"/>
+        <branch repo="nmap-local" module="nmap-7.91.tar.gz" version="7.91"/>
         <dependencies>
             <dep package="openssl" />
         </dependencies>
@@ -78,7 +78,7 @@
         makeargs='build-ncat OPENSSL_LIBS="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a"'
         makeinstallargs='install-ncat OPENSSL_LIBS="${JHBUILD_LIBDIR}/libssl.a ${JHBUILD_LIBDIR}/libcrypto.a"'
     >
-        <branch repo="nmap-local" module="nmap-7.90.tar.gz" version="7.90"/>
+        <branch repo="nmap-local" module="nmap-7.91.tar.gz" version="7.91"/>
         <dependencies>
             <dep package="openssl" />
         </dependencies>
diff --git a/mswin32/nmap.vcxproj b/mswin32/nmap.vcxproj
index e7687349d..5db867d64 100644
--- a/mswin32/nmap.vcxproj
+++ b/mswin32/nmap.vcxproj
@@ -137,6 +137,7 @@
       <AdditionalLibraryDirectories>..\libssh2\win32\Release_dll;..\..\nmap-mswin32-aux\Npcap\Lib;..\liblua;..\libpcre;..\nsock;..\nbase;..\libdnet-stripped;../libnetutil;..\..\nmap-mswin32-aux\OpenSSL\lib;..\liblinear;..\libz\contrib\vstudio\vc12\x86\ZlibDllReleaseWithoutAsm;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
       <IgnoreSpecificDefaultLibraries>%(IgnoreSpecificDefaultLibraries)</IgnoreSpecificDefaultLibraries>
       <DelayLoadDLLs>packet.dll;wpcap.dll;iphlpapi.dll;%(DelayLoadDLLs)</DelayLoadDLLs>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
       <ProgramDatabaseFile>.\$(Configuration)/nmap.pdb</ProgramDatabaseFile>
       <SubSystem>Console</SubSystem>
       <RandomizedBaseAddress>true</RandomizedBaseAddress>
@@ -174,6 +175,7 @@
       <AdditionalLibraryDirectories>..\libssh2\win32\Release_dll;..\..\nmap-mswin32-aux\Npcap\Lib;..\liblua;..\libpcre;..\nsock;..\nbase;..\libdnet-stripped;../libnetutil;..\..\nmap-mswin32-aux\OpenSSL\lib;..\liblinear;..\libz\contrib\vstudio\vc12\x86\ZlibDllReleaseWithoutAsm;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
       <IgnoreSpecificDefaultLibraries>%(IgnoreSpecificDefaultLibraries)</IgnoreSpecificDefaultLibraries>
       <DelayLoadDLLs>packet.dll;wpcap.dll;iphlpapi.dll;%(DelayLoadDLLs)</DelayLoadDLLs>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
       <ProgramDatabaseFile>.\$(Configuration)/nmap.pdb</ProgramDatabaseFile>
       <SubSystem>Console</SubSystem>
       <RandomizedBaseAddress>true</RandomizedBaseAddress>
diff --git a/ncat/docs/ncat.usage.txt b/ncat/docs/ncat.usage.txt
index 7e508f69e..6a60275f6 100644
--- a/ncat/docs/ncat.usage.txt
+++ b/ncat/docs/ncat.usage.txt
@@ -1,4 +1,4 @@
-Ncat 7.90SVN ( https://nmap.org/ncat )
+Ncat 7.91SVN ( https://nmap.org/ncat )
 Usage: ncat [options] [hostname] [port]
 
 Options taking a time assume seconds. Append 'ms' for milliseconds,
diff --git a/ncat/ncat.h b/ncat/ncat.h
index 39d88dfeb..0e7b76680 100644
--- a/ncat/ncat.h
+++ b/ncat/ncat.h
@@ -84,7 +84,7 @@
 /* Ncat information for output, etc. */
 #define NCAT_NAME "Ncat"
 #define NCAT_URL "https://nmap.org/ncat"
-#define NCAT_VERSION "7.90SVN"
+#define NCAT_VERSION "7.91SVN"
 
 #ifndef __GNUC__
 #ifndef __attribute__
diff --git a/nmap.h b/nmap.h
index a8ac17988..8e12fa6c6 100644
--- a/nmap.h
+++ b/nmap.h
@@ -121,8 +121,8 @@
 #ifndef NMAP_VERSION
 /* Edit this definition only within the quotes, because it is read from this
    file by the makefiles. */
-#define NMAP_VERSION "7.90SVN"
-#define NMAP_NUM_VERSION "7.0.90.1"
+#define NMAP_VERSION "7.91SVN"
+#define NMAP_NUM_VERSION "7.91.1.0"
 #endif
 
 #define NMAP_XMLOUTPUTVERSION "1.05"
diff --git a/nping/nping.h b/nping/nping.h
index 224a1ad12..de4dcea89 100644
--- a/nping/nping.h
+++ b/nping/nping.h
@@ -266,7 +266,7 @@
 /* General tunable defines  **************************************************/
 #define NPING_NAME "Nping"
 #define NPING_URL "https://nmap.org/nping"
-#define NPING_VERSION "0.7.90SVN"
+#define NPING_VERSION "0.7.91SVN"
 
 
 #define DEFAULT_VERBOSITY VB_0
diff --git a/nsock/src/nsock_engines.c b/nsock/src/nsock_engines.c
index dbe1ef0bd..4e33e27c4 100644
--- a/nsock/src/nsock_engines.c
+++ b/nsock/src/nsock_engines.c
@@ -100,8 +100,8 @@ extern struct io_engine engine_select;
 static struct io_engine *available_engines[] = {
   ENGINE_EPOLL
   ENGINE_KQUEUE
-  ENGINE_IOCP
   ENGINE_POLL
+  ENGINE_IOCP
   ENGINE_SELECT
   NULL
 };
diff --git a/zenmap/share/zenmap/config/zenmap_version b/zenmap/share/zenmap/config/zenmap_version
index 93102f87a..52ea140f2 100644
--- a/zenmap/share/zenmap/config/zenmap_version
+++ b/zenmap/share/zenmap/config/zenmap_version
@@ -1 +1 @@
-7.90SVN
+7.91SVN
diff --git a/zenmap/zenmapCore/Version.py b/zenmap/zenmapCore/Version.py
index ed32b5631..5fb681b95 100644
--- a/zenmap/zenmapCore/Version.py
+++ b/zenmap/zenmapCore/Version.py
@@ -1 +1 @@
-VERSION = "7.90SVN"
+VERSION = "7.91SVN"