diff --git a/README.md b/README.md
index 472d1b9..ef972fb 100644
--- a/README.md
+++ b/README.md
@@ -56,4 +56,26 @@ Building the client for each platform:
 GOOS=windows GOARCH=amd64 go build -o lczero-client.exe
 GOOS=darwin GOARCH=amd64 go build -o lczero-client_mac
 GOOS=linux GOARCH=amd64 go build -o lczero-client_linux
-```
\ No newline at end of file
+```
+
+
+# Go module support 
+
+Dependend go modules were added by executing:
+
+```
+go get 'github.com/Tilps/chess@master'    
+```
+
+gives something like:
+```
+go: downloading github.com/Tilps/chess v0.0.0-20200409092358-c35715299813
+go: github.com/Tilps/chess master => v0.0.0-20200409092358-c35715299813
+```
+
+This version number can then be used in the `go.mod` file
+
+Whenever you want to update the version do the above `go get` step and there will be a new version number generated that you can put in the existing `go.mod` file.
+
+Just use the command `go mod download` to update go's module cache.
+building should work with `go build lc0_main.go`
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..8756179
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,10 @@
+module github.com/LeelaChessZero/lczero-client
+
+go 1.15
+
+require (
+	github.com/Tilps/chess v0.0.0-20200409092358-c35715299813
+	github.com/nightlyone/lockfile v1.0.1-0.20201014160207-368fd4d5d6ae
+)
+
+replace github.com/LeelaChessZero/lczero-client => ./
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..8376b36
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,4 @@
+github.com/Tilps/chess v0.0.0-20200409092358-c35715299813 h1:9SCZ8ooOu4zJEgPuv90hPtkTT5XEIq1K0j2/Jrunsb4=
+github.com/Tilps/chess v0.0.0-20200409092358-c35715299813/go.mod h1:p5ClvMMzXkXDcSis21aF6thPWChCbR1YRrTGbEhwA6w=
+github.com/nightlyone/lockfile v1.0.1-0.20201014160207-368fd4d5d6ae h1:ZD/X4pxMoJCbiaaxKpSl5hxmr0l0TTiVrF1BPvKThU4=
+github.com/nightlyone/lockfile v1.0.1-0.20201014160207-368fd4d5d6ae/go.mod h1:rywoIealpdNse2r832aiD9jRk8ErCatROs6LzC841CI=
diff --git a/lc0_main.go b/lc0_main.go
index 0cb9b5e..d957447 100644
--- a/lc0_main.go
+++ b/lc0_main.go
@@ -29,7 +29,7 @@ import (
 	"sync"
 	"time"
 
-	"client"
+	"github.com/LeelaChessZero/lczero-client/src/client"
 
 	"github.com/Tilps/chess"
 	"github.com/nightlyone/lockfile"
@@ -52,11 +52,12 @@ var (
 	defaultLocalHost = "Unknown"
 	gpuType          = "Unknown"
 
-	localHost = flag.String("localhost", "", "Localhost name to send to the server when reporting\n(defaults to Unknown, overridden by the configuration file)")
-	hostname  = flag.String("hostname", "http://api.lczero.org", "Address of the server")
-	user      = flag.String("user", "", "Username")
-	password  = flag.String("password", "", "Password")
-	gpu       = flag.Int("gpu", -1, "GPU to use (ignored if --backend-opts used)")
+	localHost     = flag.String("localhost", "", "Localhost name to send to the server when reporting\n(defaults to Unknown, overridden by the configuration file)")
+	hostname      = flag.String("hostname", "http://api.lczero.org", "Address of the server")
+	networkMirror = flag.String("network-mirror", "", "Alternative url prefix to download networks from.")
+	user          = flag.String("user", "", "Username")
+	password      = flag.String("password", "", "Password")
+	gpu           = flag.Int("gpu", -1, "GPU to use (ignored if --backend-opts used)")
 	//	debug    = flag.Bool("debug", false, "Enable debug mode to see verbose output and save logs")
 	lc0Args  = flag.String("lc0args", "", "")
 	backopts = flag.String("backend-opts", "",
@@ -135,7 +136,7 @@ func getExtraParams() map[string]string {
 	return map[string]string{
 		"user":       *user,
 		"password":   *password,
-		"version":    "32",
+		"version":    "33",
 		"token":      strconv.Itoa(randId),
 		"train_only": strconv.FormatBool(*trainOnly),
 		"hostname":   *localHost,
@@ -365,11 +366,11 @@ func (c *cmdWrapper) launch(networkPath string, otherNetPath string, args []stri
 		testedDxNet = networkPath
 	}
 	if *backopts != "" {
-		// Check against small token blacklist, currently only "mlh", "random" and "recordreplay"
+		// Check against small token blacklist.
 		tokens := regexp.MustCompile("[,=().0-9]").Split(*backopts, -1)
 		for _, token := range tokens {
 			switch token {
-			case "mlh", "random", "recordreplay":
+			case "mlh", "random", "recordreplay", "trivial":
 				log.Fatalf("Not accepted in --backend-opts: %s", token)
 			}
 		}
@@ -895,7 +896,7 @@ func getNetwork(httpClient *http.Client, sha string, keepTime string) (string, e
 			log.Println("Waiting 10 seconds before retrying")
 			time.Sleep(10 * time.Second)
 		}
-		err = client.DownloadNetwork(httpClient, *hostname, path, sha)
+		err = client.DownloadNetwork(httpClient, *networkMirror, path, sha)
 		if err == nil {
 			return checkValidNetwork(dir, sha)
 		}
@@ -1174,6 +1175,10 @@ func main() {
 		*hostname = "http://testserver.lczero.org"
 	}
 
+	if len(*networkMirror) == 0 {
+		*networkMirror = *hostname + "/get_network?sha="
+	}
+
 	log.SetFlags(log.LstdFlags | log.Lshortfile)
 
 	if len(*settingsPath) == 0 {
@@ -1238,7 +1243,7 @@ func main() {
 		*localHost = defaultLocalHost
 	}
 
-	httpClient := &http.Client{Timeout:300 * time.Second}
+	httpClient := &http.Client{Timeout: 300 * time.Second}
 	startTime = time.Now()
 	for i := 0; ; i++ {
 		err := nextGame(httpClient, i)
diff --git a/src/client/client_http.go b/src/client/client_http.go
index 8d02b9e..d16fc3f 100644
--- a/src/client/client_http.go
+++ b/src/client/client_http.go
@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"encoding/json"
 	"errors"
-	"fmt"
 	"io"
 	"io/ioutil"
 	"log"
@@ -109,13 +108,17 @@ func UploadMatchResult(httpClient *http.Client, hostname string, match_game_id u
 	return postParams(httpClient, hostname+"/match_result", params, nil)
 }
 
-func DownloadNetwork(httpClient *http.Client, hostname string, networkPath string, sha string) error {
-	uri := hostname + fmt.Sprintf("/get_network?sha=%s", sha)
+func DownloadNetwork(httpClient *http.Client, uriPrefix string, networkPath string, sha string) error {
+	uri := uriPrefix + sha
 	r, err := httpClient.Get(uri)
 	if err != nil {
 		return err
 	}
 
+	if r.StatusCode >= 400 {
+		return errors.New("Network server gave error status.")
+	}
+
 	dir, _ := filepath.Split(networkPath)
 	out, err := ioutil.TempFile(dir, sha+"_tmp")
 	if err != nil {