diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 355f32f..9b22654 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -86,7 +86,7 @@ jobs:
           esac
 
       - name: Build tgen
-        run: mkdir -p build && cd build && CC=${{ matrix.cc }} cmake .. && make
+        run: mkdir -p build && cd build && CC=${{ matrix.cc }} cmake -DCMAKE_C_FLAGS="-Wall -Werror" .. && make
 
       - name: Install test dependencies
         run: |
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 68de9b2..773b623 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -19,6 +19,15 @@ find_package(M REQUIRED)
 pkg_check_modules(IGRAPH REQUIRED igraph)
 pkg_check_modules(GLIB REQUIRED glib-2.0)
 
+## Parse out igraph version. Needed to work around breaking API changes in igraph.
+string(REPLACE "." ";" IGRAPH_VERSION_LIST ${IGRAPH_VERSION})
+list(GET IGRAPH_VERSION_LIST 0 IGRAPH_VERSION_MAJOR)
+list(GET IGRAPH_VERSION_LIST 1 IGRAPH_VERSION_MINOR)
+list(GET IGRAPH_VERSION_LIST 2 IGRAPH_VERSION_PATCH)
+add_definitions(-DIGRAPH_VERSION_MAJOR=${IGRAPH_VERSION_MAJOR})
+add_definitions(-DIGRAPH_VERSION_MINOR=${IGRAPH_VERSION_MINOR})
+add_definitions(-DIGRAPH_VERSION_PATCH=${IGRAPH_VERSION_PATCH})
+
 ## recurse our project tree
 add_subdirectory(${CMAKE_SOURCE_DIR}/src/)
 add_subdirectory(${CMAKE_SOURCE_DIR}/test/)
diff --git a/src/tgen-graph.c b/src/tgen-graph.c
index f69b56d..c9c16c6 100644
--- a/src/tgen-graph.c
+++ b/src/tgen-graph.c
@@ -6,6 +6,7 @@
 #include <igraph.h>
 
 #include "tgen.h"
+#include "tgen-igraph-compat.h"
 
 typedef enum {
     TGEN_A_NONE = 0,
@@ -1090,7 +1091,6 @@ static GError* _tgengraph_parseGraphProperties(TGenGraph* g) {
                 "igraph_is_connected return non-success code %i", result);
     }
 
-    igraph_integer_t clusterCount;
     result = igraph_clusters(g->graph, NULL, NULL, &(g->clusterCount), IGRAPH_WEAK);
     if(result != IGRAPH_SUCCESS) {
         return g_error_new(G_MARKUP_ERROR, G_MARKUP_ERROR_PARSE,
@@ -1272,7 +1272,7 @@ TGenGraph* tgengraph_new(gchar* path) {
          * uses dlmopen to get a private namespace for each plugin. */
 
         /* use the built-in C attribute handler */
-        igraph_attribute_table_t* oldHandler = igraph_i_set_attribute_table(&igraph_cattribute_table);
+        igraph_attribute_table_t* oldHandler = igraph_set_attribute_table(&igraph_cattribute_table);
 
         g->graph = _tgengraph_loadNewGraph(g->graphPath);
         if(!g->graph) {
@@ -1292,7 +1292,7 @@ TGenGraph* tgengraph_new(gchar* path) {
         }
 
         /* replace the old handler */
-        igraph_i_set_attribute_table(oldHandler);
+        igraph_set_attribute_table(oldHandler);
     }
 
     if(error) {
diff --git a/src/tgen-igraph-compat.h b/src/tgen-igraph-compat.h
new file mode 100644
index 0000000..799be0c
--- /dev/null
+++ b/src/tgen-igraph-compat.h
@@ -0,0 +1,13 @@
+/*
+ * See LICENSE for licensing information
+ */
+
+#ifndef TGEN_IGRAPH_COMPAT_H_
+#define TGEN_IGRAPH_COMPAT_H_
+
+/* Renamed in in igraph 0.9.0 */
+#if IGRAPH_VERSION_MAJOR==0 && IGRAPH_VERSION_MINOR<9
+#define igraph_set_attribute_table igraph_i_set_attribute_table
+#endif
+
+#endif
\ No newline at end of file
diff --git a/src/tgen-log.c b/src/tgen-log.c
index 922a572..89444b5 100644
--- a/src/tgen-log.c
+++ b/src/tgen-log.c
@@ -101,7 +101,7 @@ void tgenlog_printMessage(GLogLevelFlags level, const gchar* fileName, const gin
             g_date_time_get_year(dt), g_date_time_get_month(dt), g_date_time_get_day_of_month(dt),
             g_date_time_get_hour(dt), g_date_time_get_minute(dt), g_date_time_get_second(dt),
             g_date_time_to_unix(dt), g_date_time_get_microsecond(dt),
-            _tgenlog_logLevelToString(level), fileStr, lineNum, functionName, format);
+            _tgenlog_logLevelToString(level), fileStr, lineNum, functionStr, format);
 
     gchar* messageStr = g_strdup_vprintf(newformat->str, vargs);
 
diff --git a/src/tgen-markovmodel.c b/src/tgen-markovmodel.c
index f4684c3..4fc5e79 100644
--- a/src/tgen-markovmodel.c
+++ b/src/tgen-markovmodel.c
@@ -10,6 +10,7 @@
 
 #include <igraph.h>
 
+#include "tgen-igraph-compat.h"
 #include "tgen-log.h"
 #include "tgen-markovmodel.h"
 
@@ -382,9 +383,9 @@ static gboolean _tgenmarkovmodel_checkVertexAttributes(TGenMarkovModel* mmodel,
                             "but you gave %s='%s'",
                             _tgenmarkovmodel_vertexTypeToString(VERTEX_TYPE_OBSERVATION),
                             (glong)vertexIndex,
-                            _tgenmarkovmodel_vertexTypeToString(VERTEX_ID_TO_SERVER),
-                            _tgenmarkovmodel_vertexTypeToString(VERTEX_ID_TO_ORIGIN),
-                            _tgenmarkovmodel_vertexTypeToString(VERTEX_ID_END),
+                            _tgenmarkovmodel_vertexIDToString(VERTEX_ID_TO_SERVER),
+                            _tgenmarkovmodel_vertexIDToString(VERTEX_ID_TO_ORIGIN),
+                            _tgenmarkovmodel_vertexIDToString(VERTEX_ID_END),
                             idKey, idStr);
                     isSuccess = FALSE;
                 }
@@ -881,7 +882,7 @@ static igraph_t* _tgenmarkovmodel_loadGraph(FILE* graphFileStream, const gchar*
     igraph_t* graph = g_new0(igraph_t, 1);
 
     /* make sure we use the correct attribute handler */
-    igraph_i_set_attribute_table(&igraph_cattribute_table);
+    igraph_set_attribute_table(&igraph_cattribute_table);
 
     result = igraph_read_graph_graphml(graph, graphFileStream, 0);
 
@@ -1337,12 +1338,24 @@ static guint64 _tgenmarkovmodel_generateDelay(TGenMarkovModel* mmodel,
         g_assert_not_reached();
     }
 
-    if(generatedValue > UINT64_MAX) {
-        return (guint64)UINT64_MAX;
-    } else if(generatedValue < 0) {
-        return (guint64)0;
+    double rounded = round(generatedValue);
+    if (rounded < 0) {
+        return 0;
+    /* Naively we'd check for > UINT64_MAX, but UINT64_MAX can't be precisely
+     * represented as a double. 2**64 *can* be precisely represented as a double,
+     * so we can check if it's >= that.
+     *
+     * See https://stackoverflow.com/a/17822304
+     */
+    } else if (rounded >= ldexp(1.0, 64)) {
+        return UINT64_MAX;
     } else {
-        return (guint64)round(generatedValue);
+        guint64 rv = (guint64)rounded;
+
+        /* Should "round-trip" */
+        g_assert((double)rv == rounded);
+
+        return rv;
     }
 }
 
diff --git a/src/tgen-stream.c b/src/tgen-stream.c
index eadf9b6..9315402 100644
--- a/src/tgen-stream.c
+++ b/src/tgen-stream.c
@@ -528,9 +528,9 @@ static GString* _tgenstream_getLine(TGenStream* stream) {
         }
 
         if(lineBuffer) {
-            lineBuffer = g_string_append_len(lineBuffer, &buffer[0], bytes);
+            lineBuffer = g_string_append_len(lineBuffer, (char*)&buffer[0], bytes);
         } else {
-            lineBuffer = g_string_new_len(&buffer[0], bytes);
+            lineBuffer = g_string_new_len((char*)&buffer[0], bytes);
         }
 
     }
@@ -659,6 +659,9 @@ static gboolean _tgenstream_readHeader(TGenStream* stream) {
                         tgen_info("Client running protocol version %s is unsupported", value);
                         theError = TGEN_STREAM_ERR_HEADER_VERSION;
                     }
+
+                    // Minor version number needn't match.
+                    (void)minor;
                 }
 
                 if(versions != NULL) {
@@ -1329,7 +1332,6 @@ static gboolean _tgenstream_writePayload(TGenStream* stream) {
     }
 
     gsize cumulativeSize = 0;
-    guint64 cumulativeDelay = 0;
     guint64 interPacketDelay = 0;
 
     while(cumulativeSize < limit) {
@@ -1343,7 +1345,6 @@ static gboolean _tgenstream_writePayload(TGenStream* stream) {
             /* the other end is sending us a packet, we have nothing to do.
              * but this delay should be included in the delay for our next outgoing packet. */
             interPacketDelay += obsDelay;
-            cumulativeDelay += obsDelay;
         } else if((stream->isCommander && obs == OBSERVATION_TO_SERVER)
                 || (!stream->isCommander && obs == OBSERVATION_TO_ORIGIN)) {
             /* this means we should send a packet */
@@ -1351,7 +1352,6 @@ static gboolean _tgenstream_writePayload(TGenStream* stream) {
             stream->send.expectedBytes += TGEN_MMODEL_PACKET_DATA_SIZE;
             /* since we sent a packet, now we reset the delay */
             interPacketDelay = obsDelay;
-            cumulativeDelay += obsDelay;
         } else if(obs == OBSERVATION_END) {
             /* if we have a specific requested send size, we need to reset and keep sending.
              * we never reset when requestedBytes is 0 (it either means no bytes, or end
diff --git a/src/tgen-transport.c b/src/tgen-transport.c
index f12c35b..bc72acd 100644
--- a/src/tgen-transport.c
+++ b/src/tgen-transport.c
@@ -761,22 +761,22 @@ static TGenEvent _tgentransport_receiveSocksAuth(TGenTransport* transport) {
         return TGEN_EVENT_READ;
     } else {
         /* we read it all, we can move on */
-        gboolean versionMatch = (transport->socksBuffer->str[0] == 0x01) ? TRUE : FALSE;
+        int version = transport->socksBuffer->str[0];
+        gboolean versionMatch = (version == 0x01) ? TRUE : FALSE;
         gboolean authSuccess = (transport->socksBuffer->str[1] == 0x00) ? TRUE : FALSE;
 
         g_string_free(transport->socksBuffer, TRUE);
         transport->socksBuffer = NULL;
 
-        if(authSuccess) {
-            tgen_info("socks server %s authentication succeeded with username='%s' and password='%s'",
-                    tgenpeer_toString(transport->proxy),
-                    transport->username ? transport->username : "",
-                    transport->password ? transport->password : "");
+        if (!versionMatch) {
+            tgen_warning("socks server %s returned unexpected version %d", 
+                    tgenpeer_toString(transport->proxy), version);
+            _tgentransport_changeState(transport, TGEN_XPORT_ERROR);
+            _tgentransport_changeError(transport, TGEN_XPORT_ERR_PROXY_VERSION);
+            return TGEN_EVENT_NONE;
+        }
 
-            /* now we can move on to the request */
-            _tgentransport_changeState(transport, TGEN_XPORT_PROXY_REQUEST);
-            return TGEN_EVENT_WRITE;
-        } else {
+        if (!authSuccess){
             tgen_warning("socks server %s authentication failed with username='%s' and password='%s'",
                     tgenpeer_toString(transport->proxy),
                     transport->username ? transport->username : "",
@@ -786,6 +786,15 @@ static TGenEvent _tgentransport_receiveSocksAuth(TGenTransport* transport) {
             _tgentransport_changeError(transport, TGEN_XPORT_ERR_PROXY_AUTH);
             return TGEN_EVENT_NONE;
         }
+
+        tgen_info("socks server %s authentication succeeded with username='%s' and password='%s'",
+                tgenpeer_toString(transport->proxy),
+                transport->username ? transport->username : "",
+                transport->password ? transport->password : "");
+
+        /* now we can move on to the request */
+        _tgentransport_changeState(transport, TGEN_XPORT_PROXY_REQUEST);
+        return TGEN_EVENT_WRITE;
     }
 }
 
@@ -1007,6 +1016,7 @@ static TGenEvent _tgentransport_receiveSocksResponseType(TGenTransport* transpor
         return TGEN_EVENT_READ;
     } else {
         gchar reserved = transport->socksBuffer->str[0];
+        (void)reserved;
         gchar addressType = transport->socksBuffer->str[1];
 
         g_string_free(transport->socksBuffer, TRUE);