diff --git a/Dockerfile b/Dockerfile
index 197ac830..07ac2ab5 120000
--- a/Dockerfile
+++ b/Dockerfile
@@ -1 +1 @@
-docker/Dockerfile.alpine
\ No newline at end of file
+docker/Dockerfile.ubuntu_artful
\ No newline at end of file
diff --git a/ws/IXSentryClient.cpp b/ws/IXSentryClient.cpp
index 609c0509..5e78e420 100644
--- a/ws/IXSentryClient.cpp
+++ b/ws/IXSentryClient.cpp
@@ -88,7 +88,7 @@ namespace ix
                 ss >> lineno;
 
                 Json::Value frame;
-                frame["lineno"] = lineno;
+                frame["lineno"] = Json::UInt64(lineno);
                 frame["filename"] = fileName;
                 frame["function"] = function;
 
diff --git a/ws/ixcobra/IXCobraMetricsPublisher.cpp b/ws/ixcobra/IXCobraMetricsPublisher.cpp
index f6fdc375..7fd5cc2a 100644
--- a/ws/ixcobra/IXCobraMetricsPublisher.cpp
+++ b/ws/ixcobra/IXCobraMetricsPublisher.cpp
@@ -184,7 +184,7 @@ namespace ix
         msg["data"] = data;
         msg["session"] = _session;
         msg["version"] = kVersion;
-        msg["timestamp"] = getMillisecondsSinceEpoch();
+        msg["timestamp"] = Json::UInt64(getMillisecondsSinceEpoch());
 
         {
             std::lock_guard<std::mutex> lock(_device_mutex);