diff --git a/README.md b/README.md
index 85ea0581..adebc02e 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,7 @@ The *master* branch **only** supports IETF QUIC. For Google QUIC support, please
 
 ## Guides
 
-We currently support Go 1.12+, with [Go modules](https://github.com/golang/go/wiki/Modules) support enabled.
+We currently support Go 1.13+, with [Go modules](https://github.com/golang/go/wiki/Modules) support enabled.
 
 Installing and updating dependencies:
 
diff --git a/go.mod b/go.mod
index 15a9b90d..3d6f0545 100644
--- a/go.mod
+++ b/go.mod
@@ -1,13 +1,13 @@
 module github.com/lucas-clemente/quic-go
 
-go 1.12
+go 1.13
 
 require (
 	github.com/cheekybits/genny v1.0.0
 	github.com/golang/mock v1.2.0
 	github.com/golang/protobuf v1.3.0
 	github.com/marten-seemann/qpack v0.1.0
-	github.com/marten-seemann/qtls v0.3.2
+	github.com/marten-seemann/qtls v0.3.3
 	github.com/onsi/ginkgo v1.7.0
 	github.com/onsi/gomega v1.4.3
 	golang.org/x/crypto v0.0.0-20190228161510-8dd112bcdc25
diff --git a/go.sum b/go.sum
index 5c0185cc..cfbfeb74 100644
--- a/go.sum
+++ b/go.sum
@@ -4,7 +4,6 @@ github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/golang/mock v1.2.0 h1:28o5sBqPkBsMGnC6b4MvE2TzSr5/AT4c/1fLqVGIwlk=
 github.com/golang/mock v1.2.0/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
-github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.0 h1:kbxbvI4Un1LUWKxufD+BiE6AEExYYgkQLQmLFqA1LFk=
 github.com/golang/protobuf v1.3.0/go.mod h1:Qd/q+1AKNOZr9uGQzbzCmRO6sUih6GTPZv6a1/R87v0=
@@ -12,8 +11,8 @@ github.com/hpcloud/tail v1.0.0 h1:nfCOvKYfkgYP8hkirhJocXT2+zOD8yUNjXaWfTlyFKI=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/marten-seemann/qpack v0.1.0 h1:/0M7lkda/6mus9B8u34Asqm8ZhHAAt9Ho0vniNuVSVg=
 github.com/marten-seemann/qpack v0.1.0/go.mod h1:LFt1NU/Ptjip0C2CPkhimBz5CGE3WGDAUWqna+CNTrI=
-github.com/marten-seemann/qtls v0.3.2 h1:O7awy4bHEzSX/K3h+fZig3/Vo03s/RxlxgsAk9sYamI=
-github.com/marten-seemann/qtls v0.3.2/go.mod h1:xzjG7avBwGGbdZ8dTGxlBnLArsVKLvwmjgmPuiQEcYk=
+github.com/marten-seemann/qtls v0.3.3 h1:s6E9lHmjzoOqGnEw+7F+RREKEPq4lchp1Sl+Rj5Hqsc=
+github.com/marten-seemann/qtls v0.3.3/go.mod h1:xzjG7avBwGGbdZ8dTGxlBnLArsVKLvwmjgmPuiQEcYk=
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.7.0 h1:WSHQ+IS43OoUrWtD1/bbclrwK8TTH5hzp+umCiuxHgs=
 github.com/onsi/ginkgo v1.7.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
@@ -21,7 +20,6 @@ github.com/onsi/gomega v1.4.3 h1:RE1xgDvH7imwFD45h+u2SgIfERHlS2yNG4DObb5BSKU=
 github.com/onsi/gomega v1.4.3/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
 golang.org/x/crypto v0.0.0-20190228161510-8dd112bcdc25 h1:jsG6UpNLt9iAsb0S2AGW28DveNzzgmbXR+ENoPjUeIU=
 golang.org/x/crypto v0.0.0-20190228161510-8dd112bcdc25/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/net v0.0.0-20180906233101-161cd47e91fd h1:nTDtHvHSdCn1m6ITfMRqtOd/9+7a3s8RBNOZ3eYZzJA=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190228165749-92fc7df08ae7 h1:Qe/u+eY379X4He4GBMFZYu3pmh1ML5yT1aL1ndNM1zQ=
 golang.org/x/net v0.0.0-20190228165749-92fc7df08ae7/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=