diff --git a/.travis.yml b/.travis.yml
index 6d93df75..add4db34 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -108,6 +108,30 @@ matrix:
         - sudo apt-get install -y libboost-all-dev:i386 libboost-mpi-dev:i386 libboost-mpi-python-dev:i386 libboost-python-dev:i386 libboost-python1.58-dev:i386 python:i386
     script: cd src && make -f makefile.unix -j2 STATIC="all" LDFLAGS="-static"
 
+  # Build mintcoind
+  # OS X 10.11 (El Capitan)
+  - os: osx
+    osx_image: xcode8
+    script: cd src && make -f makefile.osx -j2
+
+  # Build mintcoind static
+  # OS X 10.11 (El Capitan)
+  - os: osx
+    osx_image: xcode8
+    script: cd src && make -f makefile.osx -j2 STATIC="all" LDFLAGS="-static"
+
+  # Build mintcoind
+  # macOS 10.12 (Sierra)
+  - os: osx
+    osx_image: xcode9.2
+    script: cd src && make -f makefile.osx -j2
+
+  # Build mintcoind static
+  # macOS 10.12 (Sierra)
+  - os: osx
+    osx_image: xcode9.2
+    script: cd src && make -f makefile.osx -j2 STATIC="all" LDFLAGS="-static"
+
   # Build mintcoind
   # macOS 10.13 (High Sierra)
   - os: osx
@@ -195,11 +219,17 @@ matrix:
     sudo: required
     script: bash src/mxe-build.sh windows64-qt
 
+  # Build MintCoin-Qt
+  # macOS 10.12 (Sierra)
+  - os: osx
+    osx_image: xcode9
+    script: brew install qrencode qt && /usr/local/opt/qt/bin/qmake && make -j2
+
   # Build MintCoin-Qt
   # macOS 10.13 (High Sierra)
-  #- os: osx
-  #  osx_image: xcode10.1
-  #  script: brew install qrencode qt && /usr/local/opt/qt/bin/qmake && make -j2 
+  - os: osx
+    osx_image: xcode10.1
+    script: brew install qrencode qt && /usr/local/opt/qt/bin/qmake && make -j2 
 
   # Build MintCoin-Qt
   # macOS 10.14 (Mojave)
diff --git a/mintcoin-qt.pro b/mintcoin-qt.pro
index e8237144..c91a4ede 100644
--- a/mintcoin-qt.pro
+++ b/mintcoin-qt.pro
@@ -160,7 +160,7 @@ else {
     QMAKE_CFLAGS += -msse2
 }
 
-QMAKE_CXXFLAGS_WARN_ON = -fdiagnostics-show-option -Wall -Wextra -Wformat -Wformat-security -Wno-unused-parameter -Wstack-protector
+QMAKE_CXXFLAGS_WARN_ON = -fdiagnostics-show-option -std=c++11 -Wall -Wextra -Wformat -Wformat-security -Wno-unused-parameter -Wstack-protector
 
 # Input
 DEPENDPATH += src src/json src/qt
diff --git a/src/bignum.h b/src/bignum.h
index 75b35314..759ab7bd 100644
--- a/src/bignum.h
+++ b/src/bignum.h
@@ -7,6 +7,18 @@
 
 #include <stdexcept>
 #include <vector>
+
+#ifdef _WINDOWS
+#include <winsock2.h>
+#include <windows.h>
+#undef X509_NAME
+#undef X509_EXTENSIONS
+#undef X509_CERT_PAIR
+#undef PKCS7_ISSUER_AND_SERIAL
+#undef OCSP_REQUEST
+#undef OCSP_RESPONSE
+#endif // _WINDOWS
+
 #include <openssl/bn.h>
 
 #include "util.h" // for uint64
diff --git a/src/key.h b/src/key.h
index 427a4be1..dd2a5507 100644
--- a/src/key.h
+++ b/src/key.h
@@ -13,6 +13,16 @@
 #include "uint256.h"
 #include "hash.h"
 
+#ifdef _WINDOWS
+#include <windows.h>
+#undef X509_NAME
+#undef X509_EXTENSIONS
+#undef X509_CERT_PAIR
+#undef PKCS7_ISSUER_AND_SERIAL
+#undef OCSP_REQUEST
+#undef OCSP_RESPONSE
+#endif // _WINDOWS
+
 #include <openssl/ec.h> // for EC_KEY definition
 
 // secp160k1
diff --git a/src/leveldb/include/leveldb/status.h b/src/leveldb/include/leveldb/status.h
index 11dbd4b4..7509d268 100644
--- a/src/leveldb/include/leveldb/status.h
+++ b/src/leveldb/include/leveldb/status.h
@@ -13,7 +13,7 @@
 #ifndef STORAGE_LEVELDB_INCLUDE_STATUS_H_
 #define STORAGE_LEVELDB_INCLUDE_STATUS_H_
 
-#include <string>
+#include <string.h>
 #include "leveldb/slice.h"
 
 namespace leveldb {
diff --git a/src/makefile.unix b/src/makefile.unix
index 1e7c8c7f..0caa6b47 100644
--- a/src/makefile.unix
+++ b/src/makefile.unix
@@ -95,7 +95,7 @@ DEBUGFLAGS=-g
 
 # CXXFLAGS can be specified on the make command line, so we use xCXXFLAGS that only
 # adds some defaults in front. Unfortunately, CXXFLAGS=... $(CXXFLAGS) does not work.
-xCXXFLAGS=-O2 -pthread -Wall -Wextra -Wformat -Wformat-security -Wno-unused-parameter \
+xCXXFLAGS=-O2 -pthread -std=c++11 -Wall -Wextra -Wformat -Wformat-security -Wno-unused-parameter -Werror \
     $(DEBUGFLAGS) $(DEFS) $(HARDENING) $(CXXFLAGS)
 
 # If we have an ARM CPU, we can't use SSE2, so define as thumb.
diff --git a/src/mxe-build.sh b/src/mxe-build.sh
index fa5d980f..98ce33c8 100644
--- a/src/mxe-build.sh
+++ b/src/mxe-build.sh
@@ -28,10 +28,10 @@ fi
 # Add the MXE package repository.
 sudo apt-get update
 
-echo "deb http://pkg.mxe.cc/repos/apt/debian wheezy main" \
+echo "deb https://pkg.mxe.cc/repos/apt xenial main" \
     | sudo tee /etc/apt/sources.list.d/mxeapt.list
 sudo apt-key adv --keyserver keyserver.ubuntu.com \
-    --recv-keys D43A795B73B16ABE9643FE1AFD8FFF16DB45C6AB
+    --recv-keys C6BF758A33A3A276
 
 sudo apt-get update