diff --git a/.circleci/config.yml b/.circleci/config.yml
index d21b6b24..94697a35 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -5,7 +5,13 @@ executors:
       - image: "circleci/golang:1.14"
     environment:
       runrace: true
-
+  test-go115:
+    docker:
+      - image: "circleci/golang:1.15"
+    environment:
+      runrace: true
+      GODEBUG: x509ignoreCN=0
+ 
 jobs:
   "test": &test
     executor: test-go114
@@ -40,8 +46,12 @@ jobs:
           command: ginkgo -v -randomizeAllSpecs -trace integrationtests/self -- -qlog -metrics
   go114:
     <<: *test
+  go115:
+    <<: *test
+    executor: test-go115
 
 workflows:
   workflow:
     jobs:
       - go114
+      - go115
diff --git a/.travis.yml b/.travis.yml
index 98add497..8340f8d2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,6 +5,7 @@ language: go
 
 go:
   - "1.14.x"
+  - "1.15.x"
 
 # first part of the GOARCH workaround
 # setting the GOARCH directly doesn't work, since the value will be overwritten later
@@ -12,6 +13,7 @@ go:
 env:
   global:
     - TIMESCALE_FACTOR=20
+    - GODEBUG=x509ignoreCN=0
   matrix:
     - TRAVIS_GOARCH=amd64 TESTMODE=unit
     - TRAVIS_GOARCH=amd64 TESTMODE=integration
diff --git a/go.mod b/go.mod
index 141c950d..5951e730 100644
--- a/go.mod
+++ b/go.mod
@@ -6,10 +6,11 @@ require (
 	github.com/cheekybits/genny v1.0.0
 	github.com/francoispqt/gojay v1.2.13
 	github.com/golang/groupcache v0.0.0-20191027212112-611e8accdfc9 // indirect
-	github.com/golang/mock v1.4.0
+	github.com/golang/mock v1.4.4
 	github.com/golang/protobuf v1.4.2
 	github.com/marten-seemann/qpack v0.2.0
 	github.com/marten-seemann/qtls v0.10.0
+	github.com/marten-seemann/qtls-go1-15 v0.1.0
 	github.com/onsi/ginkgo v1.14.0
 	github.com/onsi/gomega v1.10.1
 	go.opencensus.io v0.22.2
diff --git a/go.sum b/go.sum
index da41e68c..e54114a1 100644
--- a/go.sum
+++ b/go.sum
@@ -41,6 +41,8 @@ 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/mock v1.4.0 h1:Rd1kQnQu0Hq3qvJppYSG0HtP+f5LPPUiDswTLiEegLg=
 github.com/golang/mock v1.4.0/go.mod h1:UOMv5ysSaYNkG+OFQykRIcU/QvvxJf3p21QfJ2Bt3cw=
+github.com/golang/mock v1.4.4 h1:l75CXGRSwbaYNpl/Z2X1XIIAMSCquvXgpVZDhwEIJsc=
+github.com/golang/mock v1.4.4/go.mod h1:l3mdAwkq5BuhzHwde/uurv3sEJeZMXNpwsxVWU71h+4=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.1 h1:YF8+flBXS5eO826T4nzqPrxfhQThhXl0YzfuUPu4SBg=
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
@@ -85,6 +87,8 @@ github.com/marten-seemann/qpack v0.2.0 h1:/r1rhZoOmgxVKBqPNnYilZBDEyw+6OUHCbBzA5
 github.com/marten-seemann/qpack v0.2.0/go.mod h1:F7Gl5L1jIgN1D11ucXefiuJS9UMVP2opoCp2jDKb7wc=
 github.com/marten-seemann/qtls v0.10.0 h1:ECsuYUKalRL240rRD4Ri33ISb7kAQ3qGDlrrl55b2pc=
 github.com/marten-seemann/qtls v0.10.0/go.mod h1:UvMd1oaYDACI99/oZUYLzMCkBXQVT0aGm99sJhbT8hs=
+github.com/marten-seemann/qtls-go1-15 v0.1.0 h1:i/YPXVxz8q9umso/5y474CNcHmTpA+5DH+mFPjx6PZg=
+github.com/marten-seemann/qtls-go1-15 v0.1.0/go.mod h1:GyFwywLKkRt+6mfU99csTEY1joMZz5vmB1WNZH3P81I=
 github.com/matttproud/golang_protobuf_extensions v1.0.1 h1:4hp9jkHxhMHkqkrB3Ix0jegS5sx/RkqARlsWZ6pIwiU=
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
 github.com/microcosm-cc/bluemonday v1.0.1/go.mod h1:hsXNsILzKxV+sX77C5b8FSuKF00vh2OMYv+xgHpAMF4=
diff --git a/integrationtests/self/handshake_test.go b/integrationtests/self/handshake_test.go
index bacee08f..699b70a7 100644
--- a/integrationtests/self/handshake_test.go
+++ b/integrationtests/self/handshake_test.go
@@ -371,7 +371,6 @@ var _ = Describe("Handshake tests", func() {
 				Expect(err).ToNot(HaveOccurred())
 				cs := sess.ConnectionState()
 				Expect(cs.NegotiatedProtocol).To(Equal(alpn))
-				Expect(cs.NegotiatedProtocolIsMutual).To(BeTrue())
 				close(done)
 			}()
 
@@ -384,7 +383,6 @@ var _ = Describe("Handshake tests", func() {
 			defer sess.CloseWithError(0, "")
 			cs := sess.ConnectionState()
 			Expect(cs.NegotiatedProtocol).To(Equal(alpn))
-			Expect(cs.NegotiatedProtocolIsMutual).To(BeTrue())
 			Eventually(done).Should(BeClosed())
 			Expect(ln.Close()).To(Succeed())
 		})
diff --git a/internal/qtls/interface.go b/internal/qtls/go114.go
similarity index 99%
rename from internal/qtls/interface.go
rename to internal/qtls/go114.go
index e0f3747f..79ad6f0b 100644
--- a/internal/qtls/interface.go
+++ b/internal/qtls/go114.go
@@ -1,3 +1,5 @@
+// +build !go1.15
+
 package qtls
 
 import (
diff --git a/internal/qtls/go114_test.go b/internal/qtls/go114_test.go
new file mode 100644
index 00000000..8942a988
--- /dev/null
+++ b/internal/qtls/go114_test.go
@@ -0,0 +1,19 @@
+// +build !go1.15
+
+package qtls
+
+import (
+	"crypto/tls"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("qtls wrapper", func() {
+	It("gets cipher suites", func() {
+		for _, id := range []uint16{tls.TLS_AES_128_GCM_SHA256, tls.TLS_AES_256_GCM_SHA384, tls.TLS_CHACHA20_POLY1305_SHA256} {
+			cs := CipherSuiteTLS13ByID(id)
+			Expect(cs.ID).To(Equal(id))
+		}
+	})
+})
diff --git a/internal/qtls/go115.go b/internal/qtls/go115.go
new file mode 100644
index 00000000..a64728c7
--- /dev/null
+++ b/internal/qtls/go115.go
@@ -0,0 +1,108 @@
+// +build go1.15
+
+package qtls
+
+import (
+	"crypto"
+	"crypto/cipher"
+	"net"
+	"unsafe"
+
+	qtls "github.com/marten-seemann/qtls-go1-15"
+)
+
+type (
+	// Alert is a TLS alert
+	Alert = qtls.Alert
+	// A Certificate is qtls.Certificate.
+	Certificate = qtls.Certificate
+	// CertificateRequestInfo contains inforamtion about a certificate request.
+	CertificateRequestInfo = qtls.CertificateRequestInfo
+	// A CipherSuiteTLS13 is a cipher suite for TLS 1.3
+	CipherSuiteTLS13 = qtls.CipherSuiteTLS13
+	// ClientHelloInfo contains information about a ClientHello.
+	ClientHelloInfo = qtls.ClientHelloInfo
+	// ClientSessionCache is a cache used for session resumption.
+	ClientSessionCache = qtls.ClientSessionCache
+	// ClientSessionState is a state needed for session resumption.
+	ClientSessionState = qtls.ClientSessionState
+	// A Config is a qtls.Config.
+	Config = qtls.Config
+	// A Conn is a qtls.Conn.
+	Conn = qtls.Conn
+	// ConnectionState contains information about the state of the connection.
+	ConnectionState = qtls.ConnectionStateWith0RTT
+	// EncryptionLevel is the encryption level of a message.
+	EncryptionLevel = qtls.EncryptionLevel
+	// Extension is a TLS extension
+	Extension = qtls.Extension
+	// ExtraConfig is the qtls.ExtraConfig
+	ExtraConfig = qtls.ExtraConfig
+	// RecordLayer is a qtls RecordLayer.
+	RecordLayer = qtls.RecordLayer
+)
+
+const (
+	// EncryptionHandshake is the Handshake encryption level
+	EncryptionHandshake = qtls.EncryptionHandshake
+	// Encryption0RTT is the 0-RTT encryption level
+	Encryption0RTT = qtls.Encryption0RTT
+	// EncryptionApplication is the application data encryption level
+	EncryptionApplication = qtls.EncryptionApplication
+)
+
+// CipherSuiteName gets the name of a cipher suite.
+func CipherSuiteName(id uint16) string {
+	return qtls.CipherSuiteName(id)
+}
+
+// HkdfExtract generates a pseudorandom key for use with Expand from an input secret and an optional independent salt.
+func HkdfExtract(hash crypto.Hash, newSecret, currentSecret []byte) []byte {
+	return qtls.HkdfExtract(hash, newSecret, currentSecret)
+}
+
+// HkdfExpandLabel HKDF expands a label
+func HkdfExpandLabel(hash crypto.Hash, secret, hashValue []byte, label string, L int) []byte {
+	return qtls.HkdfExpandLabel(hash, secret, hashValue, label, L)
+}
+
+// AEADAESGCMTLS13 creates a new AES-GCM AEAD for TLS 1.3
+func AEADAESGCMTLS13(key, fixedNonce []byte) cipher.AEAD {
+	return qtls.AEADAESGCMTLS13(key, fixedNonce)
+}
+
+// Client returns a new TLS client side connection.
+func Client(conn net.Conn, config *Config, extraConfig *ExtraConfig) *Conn {
+	return qtls.Client(conn, config, extraConfig)
+}
+
+// Server returns a new TLS server side connection.
+func Server(conn net.Conn, config *Config, extraConfig *ExtraConfig) *Conn {
+	return qtls.Server(conn, config, extraConfig)
+}
+
+func GetConnectionState(conn *Conn) ConnectionState {
+	return conn.ConnectionStateWith0RTT()
+}
+
+type cipherSuiteTLS13 struct {
+	ID     uint16
+	KeyLen int
+	AEAD   func(key, fixedNonce []byte) cipher.AEAD
+	Hash   crypto.Hash
+}
+
+//go:linkname cipherSuiteTLS13ByID github.com/marten-seemann/qtls-go1-15.cipherSuiteTLS13ByID
+func cipherSuiteTLS13ByID(id uint16) *cipherSuiteTLS13
+
+// CipherSuiteTLS13ByID gets a TLS 1.3 cipher suite.
+func CipherSuiteTLS13ByID(id uint16) *CipherSuiteTLS13 {
+	val := cipherSuiteTLS13ByID(id)
+	cs := (*cipherSuiteTLS13)(unsafe.Pointer(val))
+	return &qtls.CipherSuiteTLS13{
+		ID:     cs.ID,
+		KeyLen: cs.KeyLen,
+		AEAD:   cs.AEAD,
+		Hash:   cs.Hash,
+	}
+}
diff --git a/internal/qtls/go115_test.go b/internal/qtls/go115_test.go
new file mode 100644
index 00000000..d5abc550
--- /dev/null
+++ b/internal/qtls/go115_test.go
@@ -0,0 +1,19 @@
+// +build go1.15
+
+package qtls
+
+import (
+	"crypto/tls"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("qtls wrapper", func() {
+	It("gets cipher suites", func() {
+		for _, id := range []uint16{tls.TLS_AES_128_GCM_SHA256, tls.TLS_AES_256_GCM_SHA384, tls.TLS_CHACHA20_POLY1305_SHA256} {
+			cs := CipherSuiteTLS13ByID(id)
+			Expect(cs.ID).To(Equal(id))
+		}
+	})
+})
diff --git a/internal/qtls/qtls.go b/internal/qtls/qtls.go
index c281c37e..b42b43fa 100644
--- a/internal/qtls/qtls.go
+++ b/internal/qtls/qtls.go
@@ -1,3 +1,5 @@
+// +build !go1.15
+
 package qtls
 
 // This package uses unsafe to convert between:
diff --git a/internal/qtls/qtls_test.go b/internal/qtls/qtls_test.go
index 0bdd4052..90b97c39 100644
--- a/internal/qtls/qtls_test.go
+++ b/internal/qtls/qtls_test.go
@@ -1,3 +1,5 @@
+// +build !go1.15
+
 package qtls
 
 import (
diff --git a/internal/qtls/structs_equal.go b/internal/qtls/structs_equal.go
index 7df0423a..dd846372 100644
--- a/internal/qtls/structs_equal.go
+++ b/internal/qtls/structs_equal.go
@@ -1,3 +1,5 @@
+// +build !go1.15
+
 package qtls
 
 import "reflect"
diff --git a/internal/qtls/structs_equal_test.go b/internal/qtls/structs_equal_test.go
index 2a2f46c2..ec570afb 100644
--- a/internal/qtls/structs_equal_test.go
+++ b/internal/qtls/structs_equal_test.go
@@ -1,3 +1,5 @@
+// +build !go1.15
+
 package qtls
 
 import (