diff --git a/common.go b/common.go
index 7cfc1b16..822ae449 100644
--- a/common.go
+++ b/common.go
@@ -85,6 +85,7 @@ const (
 	extensionSignatureAlgorithms     uint16 = 13
 	extensionALPN                    uint16 = 16
 	extensionSCT                     uint16 = 18
+	extensionDelegatedCredentials    uint16 = 34
 	extensionSessionTicket           uint16 = 35
 	extensionPreSharedKey            uint16 = 41
 	extensionEarlyData               uint16 = 42
@@ -95,6 +96,7 @@ const (
 	extensionSignatureAlgorithmsCert uint16 = 50
 	extensionKeyShare                uint16 = 51
 	extensionNextProtoNeg            uint16 = 13172 // not IANA assigned
+	extensionALPS                    uint16 = 17513
 	extensionRenegotiationInfo       uint16 = 0xff01
 )
 
diff --git a/u_common.go b/u_common.go
index 668a677b..febc4d12 100644
--- a/u_common.go
+++ b/u_common.go
@@ -146,22 +146,32 @@ var (
 	HelloRandomizedNoALPN = ClientHelloID{helloRandomizedNoALPN, helloAutoVers, nil}
 
 	// The rest will will parrot given browser.
-	HelloFirefox_Auto = HelloFirefox_65
+	HelloFirefox_Auto = HelloFirefox_102
 	HelloFirefox_55   = ClientHelloID{helloFirefox, "55", nil}
 	HelloFirefox_56   = ClientHelloID{helloFirefox, "56", nil}
 	HelloFirefox_63   = ClientHelloID{helloFirefox, "63", nil}
 	HelloFirefox_65   = ClientHelloID{helloFirefox, "65", nil}
+	HelloFirefox_99   = ClientHelloID{helloFirefox, "99", nil}
+	HelloFirefox_102  = ClientHelloID{helloFirefox, "102", nil}
 
-	HelloChrome_Auto = HelloChrome_83
+	HelloChrome_Auto = HelloChrome_102
 	HelloChrome_58   = ClientHelloID{helloChrome, "58", nil}
 	HelloChrome_62   = ClientHelloID{helloChrome, "62", nil}
 	HelloChrome_70   = ClientHelloID{helloChrome, "70", nil}
 	HelloChrome_72   = ClientHelloID{helloChrome, "72", nil}
 	HelloChrome_83   = ClientHelloID{helloChrome, "83", nil}
+	HelloChrome_87   = ClientHelloID{helloChrome, "87", nil}
+	HelloChrome_96   = ClientHelloID{helloChrome, "96", nil}
+	HelloChrome_100  = ClientHelloID{helloChrome, "100", nil}
+	HelloChrome_102  = ClientHelloID{helloChrome, "102", nil}
 
-	HelloIOS_Auto = HelloIOS_12_1
+	HelloIOS_Auto = HelloIOS_14
 	HelloIOS_11_1 = ClientHelloID{helloIOS, "111", nil} // legacy "111" means 11.1
 	HelloIOS_12_1 = ClientHelloID{helloIOS, "12.1", nil}
+	HelloIOS_13   = ClientHelloID{helloIOS, "13", nil}
+	HelloIOS_14   = ClientHelloID{helloIOS, "14", nil}
+
+	HelloAndroid_11_OkHttp = ClientHelloID{helloAndroid, "11", nil}
 )
 
 // based on spec's GreaseStyle, GREASE_PLACEHOLDER may be replaced by another GREASE value
diff --git a/u_parrots.go b/u_parrots.go
index eeda357b..43568638 100644
--- a/u_parrots.go
+++ b/u_parrots.go
@@ -284,6 +284,235 @@ func utlsIdToSpec(id ClientHelloID) (ClientHelloSpec, error) {
 				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle},
 			},
 		}, nil
+	case HelloChrome_87:
+		return ClientHelloSpec{
+			CipherSuites: []uint16{
+				GREASE_PLACEHOLDER,
+				TLS_AES_128_GCM_SHA256,
+				TLS_AES_256_GCM_SHA384,
+				TLS_CHACHA20_POLY1305_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_RSA_WITH_AES_128_CBC_SHA,
+				TLS_RSA_WITH_AES_256_CBC_SHA,
+			},
+			CompressionMethods: []byte{
+				0x00, // compressionNone
+			},
+			Extensions: []TLSExtension{
+				&UtlsGREASEExtension{},
+				&SNIExtension{},
+				&UtlsExtendedMasterSecretExtension{},
+				&RenegotiationInfoExtension{Renegotiation: RenegotiateOnceAsClient},
+				&SupportedCurvesExtension{[]CurveID{
+					CurveID(GREASE_PLACEHOLDER),
+					X25519,
+					CurveP256,
+					CurveP384,
+				}},
+				&SupportedPointsExtension{SupportedPoints: []byte{
+					0x00, // pointFormatUncompressed
+				}},
+				&SessionTicketExtension{},
+				&ALPNExtension{AlpnProtocols: []string{"h2", "http/1.1"}},
+				&StatusRequestExtension{},
+				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{
+					ECDSAWithP256AndSHA256,
+					PSSWithSHA256,
+					PKCS1WithSHA256,
+					ECDSAWithP384AndSHA384,
+					PSSWithSHA384,
+					PKCS1WithSHA384,
+					PSSWithSHA512,
+					PKCS1WithSHA512,
+				}},
+				&SCTExtension{},
+				&KeyShareExtension{[]KeyShare{
+					{Group: CurveID(GREASE_PLACEHOLDER), Data: []byte{0}},
+					{Group: X25519},
+				}},
+				&PSKKeyExchangeModesExtension{[]uint8{
+					PskModeDHE,
+				}},
+				&SupportedVersionsExtension{[]uint16{
+					GREASE_PLACEHOLDER,
+					VersionTLS13,
+					VersionTLS12,
+					VersionTLS11,
+					VersionTLS10,
+				}},
+				&UtlsCompressCertExtension{[]CertCompressionAlgo{
+					CertCompressionBrotli,
+				}},
+				&UtlsGREASEExtension{},
+				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle},
+			},
+		}, nil
+	case HelloChrome_96:
+		return ClientHelloSpec{
+			CipherSuites: []uint16{
+				GREASE_PLACEHOLDER,
+				TLS_AES_128_GCM_SHA256,
+				TLS_AES_256_GCM_SHA384,
+				TLS_CHACHA20_POLY1305_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_RSA_WITH_AES_128_CBC_SHA,
+				TLS_RSA_WITH_AES_256_CBC_SHA,
+			},
+			CompressionMethods: []byte{
+				0x00, // compressionNone
+			},
+			Extensions: []TLSExtension{
+				&UtlsGREASEExtension{},
+				&SNIExtension{},
+				&UtlsExtendedMasterSecretExtension{},
+				&RenegotiationInfoExtension{Renegotiation: RenegotiateOnceAsClient},
+				&SupportedCurvesExtension{[]CurveID{
+					CurveID(GREASE_PLACEHOLDER),
+					X25519,
+					CurveP256,
+					CurveP384,
+				}},
+				&SupportedPointsExtension{SupportedPoints: []byte{
+					0x00, // pointFormatUncompressed
+				}},
+				&SessionTicketExtension{},
+				&ALPNExtension{AlpnProtocols: []string{"h2", "http/1.1"}},
+				&StatusRequestExtension{},
+				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{
+					ECDSAWithP256AndSHA256,
+					PSSWithSHA256,
+					PKCS1WithSHA256,
+					ECDSAWithP384AndSHA384,
+					PSSWithSHA384,
+					PKCS1WithSHA384,
+					PSSWithSHA512,
+					PKCS1WithSHA512,
+				}},
+				&SCTExtension{},
+				&KeyShareExtension{[]KeyShare{
+					{Group: CurveID(GREASE_PLACEHOLDER), Data: []byte{0}},
+					{Group: X25519},
+				}},
+				&PSKKeyExchangeModesExtension{[]uint8{
+					PskModeDHE,
+				}},
+				&SupportedVersionsExtension{[]uint16{
+					GREASE_PLACEHOLDER,
+					VersionTLS13,
+					VersionTLS12,
+					VersionTLS11,
+					VersionTLS10,
+				}},
+				&UtlsCompressCertExtension{[]CertCompressionAlgo{
+					CertCompressionBrotli,
+				}},
+				&ApplicationSettingsExtension{SupportedProtocols: []string{"h2"}},
+				&UtlsGREASEExtension{},
+				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle},
+			},
+		}, nil
+	case HelloChrome_100:
+		signatureScheme := []SignatureScheme{
+			ECDSAWithP256AndSHA256,
+			ECDSAWithP384AndSHA384,
+			ECDSAWithP521AndSHA512,
+			PSSWithSHA256,
+			PSSWithSHA384,
+			PSSWithSHA512,
+			0x0809,
+			0x080a,
+			0x080b,
+			PKCS1WithSHA256,
+			PKCS1WithSHA384,
+			PKCS1WithSHA512,
+			0x0402,
+			0x0303,
+			0x0301,
+			0x0302,
+			0x0203,
+			0x0201,
+			0x0202,
+		}
+		return ClientHelloSpec{
+			CipherSuites: []uint16{
+				GREASE_PLACEHOLDER,
+				TLS_AES_128_GCM_SHA256,
+				TLS_AES_256_GCM_SHA384,
+				TLS_CHACHA20_POLY1305_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_RSA_WITH_AES_128_CBC_SHA,
+				TLS_RSA_WITH_AES_256_CBC_SHA,
+			},
+			CompressionMethods: []byte{
+				0x00, // compressionNone
+			},
+			Extensions: []TLSExtension{
+				&UtlsGREASEExtension{},
+				&SNIExtension{},
+				&UtlsExtendedMasterSecretExtension{},
+				&RenegotiationInfoExtension{},
+				&SupportedCurvesExtension{[]CurveID{
+					GREASE_PLACEHOLDER,
+					X25519,
+					CurveP256,
+					CurveP384,
+				}},
+				&SupportedPointsExtension{SupportedPoints: []byte{
+					0x00, // pointFormatUncompressed
+				}},
+				&SessionTicketExtension{},
+				&ALPNExtension{AlpnProtocols: []string{"h2", "http/1.1"}},
+				&StatusRequestExtension{},
+				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: signatureScheme},
+				&SCTExtension{},
+				&KeyShareExtension{[]KeyShare{
+					{Group: CurveID(GREASE_PLACEHOLDER), Data: []byte{0}},
+					{Group: X25519},
+				}},
+				&PSKKeyExchangeModesExtension{[]uint8{
+					PskModeDHE,
+				}},
+				&SupportedVersionsExtension{[]uint16{
+					VersionTLS13,
+					VersionTLS12,
+					VersionTLS11,
+					VersionTLS10,
+				}},
+				&UtlsCompressCertExtension{[]CertCompressionAlgo{
+					CertCompressionBrotli,
+				}},
+				&UtlsGREASEExtension{},
+				&ApplicationSettingsExtension{SupportedProtocols: []string{"h2"}},
+				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle},
+			},
+		}, nil
 	case HelloFirefox_55, HelloFirefox_56:
 		return ClientHelloSpec{
 			TLSVersMax: VersionTLS12,
@@ -313,9 +542,232 @@ func utlsIdToSpec(id ClientHelloID) (ClientHelloSpec, error) {
 				&SupportedCurvesExtension{[]CurveID{X25519, CurveP256, CurveP384, CurveP521}},
 				&SupportedPointsExtension{SupportedPoints: []byte{pointFormatUncompressed}},
 				&SessionTicketExtension{},
-				&ALPNExtension{AlpnProtocols: []string{"h2", "http/1.1"}},
+				&ALPNExtension{AlpnProtocols: []string{"h2", "http/1.1"}},
+				&StatusRequestExtension{},
+				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{
+					ECDSAWithP256AndSHA256,
+					ECDSAWithP384AndSHA384,
+					ECDSAWithP521AndSHA512,
+					PSSWithSHA256,
+					PSSWithSHA384,
+					PSSWithSHA512,
+					PKCS1WithSHA256,
+					PKCS1WithSHA384,
+					PKCS1WithSHA512,
+					ECDSAWithSHA1,
+					PKCS1WithSHA1},
+				},
+				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle},
+			},
+			GetSessionID: nil,
+		}, nil
+	case HelloFirefox_63, HelloFirefox_65:
+		return ClientHelloSpec{
+			TLSVersMin: VersionTLS10,
+			TLSVersMax: VersionTLS13,
+			CipherSuites: []uint16{
+				TLS_AES_128_GCM_SHA256,
+				TLS_CHACHA20_POLY1305_SHA256,
+				TLS_AES_256_GCM_SHA384,
+				TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+				TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				FAKE_TLS_DHE_RSA_WITH_AES_128_CBC_SHA,
+				FAKE_TLS_DHE_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_AES_128_CBC_SHA,
+				TLS_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_3DES_EDE_CBC_SHA,
+			},
+			CompressionMethods: []byte{
+				compressionNone,
+			},
+			Extensions: []TLSExtension{
+				&SNIExtension{},
+				&UtlsExtendedMasterSecretExtension{},
+				&RenegotiationInfoExtension{Renegotiation: RenegotiateOnceAsClient},
+				&SupportedCurvesExtension{[]CurveID{
+					X25519,
+					CurveP256,
+					CurveP384,
+					CurveP521,
+					CurveID(FakeFFDHE2048),
+					CurveID(FakeFFDHE3072),
+				}},
+				&SupportedPointsExtension{SupportedPoints: []byte{
+					pointFormatUncompressed,
+				}},
+				&SessionTicketExtension{},
+				&ALPNExtension{AlpnProtocols: []string{"h2", "http/1.1"}},
+				&StatusRequestExtension{},
+				&KeyShareExtension{[]KeyShare{
+					{Group: X25519},
+					{Group: CurveP256},
+				}},
+				&SupportedVersionsExtension{[]uint16{
+					VersionTLS13,
+					VersionTLS12,
+					VersionTLS11,
+					VersionTLS10}},
+				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{
+					ECDSAWithP256AndSHA256,
+					ECDSAWithP384AndSHA384,
+					ECDSAWithP521AndSHA512,
+					PSSWithSHA256,
+					PSSWithSHA384,
+					PSSWithSHA512,
+					PKCS1WithSHA256,
+					PKCS1WithSHA384,
+					PKCS1WithSHA512,
+					ECDSAWithSHA1,
+					PKCS1WithSHA1,
+				}},
+				&PSKKeyExchangeModesExtension{[]uint8{pskModeDHE}},
+				&FakeRecordSizeLimitExtension{0x4001},
+				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle},
+			}}, nil
+	case HelloChrome_102:
+		return ClientHelloSpec{
+			CipherSuites: []uint16{
+				GREASE_PLACEHOLDER,
+				TLS_AES_128_GCM_SHA256,
+				TLS_AES_256_GCM_SHA384,
+				TLS_CHACHA20_POLY1305_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_RSA_WITH_AES_128_CBC_SHA,
+				TLS_RSA_WITH_AES_256_CBC_SHA,
+			},
+			CompressionMethods: []byte{
+				0x00, // compressionNone
+			},
+			Extensions: []TLSExtension{
+				&UtlsGREASEExtension{},
+				&SNIExtension{},
+				&UtlsExtendedMasterSecretExtension{},
+				&RenegotiationInfoExtension{Renegotiation: RenegotiateOnceAsClient},
+				&SupportedCurvesExtension{[]CurveID{
+					GREASE_PLACEHOLDER,
+					X25519,
+					CurveP256,
+					CurveP384,
+				}},
+				&SupportedPointsExtension{SupportedPoints: []byte{
+					0x00, // pointFormatUncompressed
+				}},
+				&SessionTicketExtension{},
+				&ALPNExtension{AlpnProtocols: []string{"h2", "http/1.1"}},
+				&StatusRequestExtension{},
+				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{
+					ECDSAWithP256AndSHA256,
+					PSSWithSHA256,
+					PKCS1WithSHA256,
+					ECDSAWithP384AndSHA384,
+					PSSWithSHA384,
+					PKCS1WithSHA384,
+					PSSWithSHA512,
+					PKCS1WithSHA512,
+				}},
+				&SCTExtension{},
+				&KeyShareExtension{[]KeyShare{
+					{Group: CurveID(GREASE_PLACEHOLDER), Data: []byte{0}},
+					{Group: X25519},
+				}},
+				&PSKKeyExchangeModesExtension{[]uint8{
+					PskModeDHE,
+				}},
+				&SupportedVersionsExtension{[]uint16{
+					GREASE_PLACEHOLDER,
+					VersionTLS13,
+					VersionTLS12,
+				}},
+				&UtlsCompressCertExtension{[]CertCompressionAlgo{
+					CertCompressionBrotli,
+				}},
+				&ApplicationSettingsExtension{SupportedProtocols: []string{"h2"}},
+				&UtlsGREASEExtension{},
+				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle},
+			},
+		}, nil
+
+	case HelloFirefox_99:
+		return ClientHelloSpec{
+			TLSVersMin: VersionTLS10,
+			TLSVersMax: VersionTLS13,
+			CipherSuites: []uint16{
+				TLS_AES_128_GCM_SHA256,
+				TLS_CHACHA20_POLY1305_SHA256,
+				TLS_AES_256_GCM_SHA384,
+				TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+				TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_RSA_WITH_AES_128_CBC_SHA,
+				TLS_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_3DES_EDE_CBC_SHA,
+			},
+			CompressionMethods: []byte{
+				compressionNone,
+			},
+			Extensions: []TLSExtension{
+				&SNIExtension{},                      //server_name
+				&UtlsExtendedMasterSecretExtension{}, //extended_master_secret
+				&RenegotiationInfoExtension{Renegotiation: RenegotiateOnceAsClient}, //extensionRenegotiationInfo
+				&SupportedCurvesExtension{[]CurveID{ //supported_groups
+					X25519,
+					CurveP256,
+					CurveP384,
+					CurveP521,
+					CurveID(FakeFFDHE2048),
+					CurveID(FakeFFDHE3072),
+				}},
+				&SupportedPointsExtension{SupportedPoints: []byte{ //ec_point_formats
+					pointFormatUncompressed,
+				}},
+				&SessionTicketExtension{},
+				&ALPNExtension{AlpnProtocols: []string{"h2", "http/1.1"}}, //application_layer_protocol_negotiation
 				&StatusRequestExtension{},
-				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{
+				&DelegatedCredentialsExtension{
+					AlgorithmsSignature: []SignatureScheme{ //signature_algorithms
+						ECDSAWithP256AndSHA256,
+						ECDSAWithP384AndSHA384,
+						ECDSAWithP521AndSHA512,
+						ECDSAWithSHA1,
+					},
+				},
+				&KeyShareExtension{[]KeyShare{
+					{Group: X25519},
+					{Group: CurveP256}, //key_share
+				}},
+				&SupportedVersionsExtension{[]uint16{
+					VersionTLS13, //supported_versions
+					VersionTLS12,
+					VersionTLS11,
+					VersionTLS10,
+				}},
+				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{ //signature_algorithms
 					ECDSAWithP256AndSHA256,
 					ECDSAWithP384AndSHA384,
 					ECDSAWithP521AndSHA512,
@@ -326,13 +778,15 @@ func utlsIdToSpec(id ClientHelloID) (ClientHelloSpec, error) {
 					PKCS1WithSHA384,
 					PKCS1WithSHA512,
 					ECDSAWithSHA1,
-					PKCS1WithSHA1},
-				},
-				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle},
-			},
-			GetSessionID: nil,
-		}, nil
-	case HelloFirefox_63, HelloFirefox_65:
+					PKCS1WithSHA1,
+				}},
+				&PSKKeyExchangeModesExtension{[]uint8{ //psk_key_exchange_modes
+					PskModeDHE,
+				}},
+				&FakeRecordSizeLimitExtension{Limit: 0x4001},             //record_size_limit
+				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle}, //padding
+			}}, nil
+	case HelloFirefox_102:
 		return ClientHelloSpec{
 			TLSVersMin: VersionTLS10,
 			TLSVersMax: VersionTLS13,
@@ -350,20 +804,19 @@ func utlsIdToSpec(id ClientHelloID) (ClientHelloSpec, error) {
 				TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
 				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
 				TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
-				FAKE_TLS_DHE_RSA_WITH_AES_128_CBC_SHA,
-				FAKE_TLS_DHE_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_RSA_WITH_AES_256_GCM_SHA384,
 				TLS_RSA_WITH_AES_128_CBC_SHA,
 				TLS_RSA_WITH_AES_256_CBC_SHA,
-				TLS_RSA_WITH_3DES_EDE_CBC_SHA,
 			},
 			CompressionMethods: []byte{
 				compressionNone,
 			},
 			Extensions: []TLSExtension{
-				&SNIExtension{},
-				&UtlsExtendedMasterSecretExtension{},
-				&RenegotiationInfoExtension{Renegotiation: RenegotiateOnceAsClient},
-				&SupportedCurvesExtension{[]CurveID{
+				&SNIExtension{},                      //server_name
+				&UtlsExtendedMasterSecretExtension{}, //extended_master_secret
+				&RenegotiationInfoExtension{Renegotiation: RenegotiateOnceAsClient}, //extensionRenegotiationInfo
+				&SupportedCurvesExtension{[]CurveID{ //supported_groups
 					X25519,
 					CurveP256,
 					CurveP384,
@@ -371,22 +824,29 @@ func utlsIdToSpec(id ClientHelloID) (ClientHelloSpec, error) {
 					CurveID(FakeFFDHE2048),
 					CurveID(FakeFFDHE3072),
 				}},
-				&SupportedPointsExtension{SupportedPoints: []byte{
+				&SupportedPointsExtension{SupportedPoints: []byte{ //ec_point_formats
 					pointFormatUncompressed,
 				}},
 				&SessionTicketExtension{},
-				&ALPNExtension{AlpnProtocols: []string{"h2", "http/1.1"}},
+				&ALPNExtension{AlpnProtocols: []string{"h2"}}, //application_layer_protocol_negotiation
 				&StatusRequestExtension{},
+				&DelegatedCredentialsExtension{
+					AlgorithmsSignature: []SignatureScheme{ //signature_algorithms
+						ECDSAWithP256AndSHA256,
+						ECDSAWithP384AndSHA384,
+						ECDSAWithP521AndSHA512,
+						ECDSAWithSHA1,
+					},
+				},
 				&KeyShareExtension{[]KeyShare{
 					{Group: X25519},
-					{Group: CurveP256},
+					{Group: CurveP256}, //key_share
 				}},
 				&SupportedVersionsExtension{[]uint16{
-					VersionTLS13,
+					VersionTLS13, //supported_versions
 					VersionTLS12,
-					VersionTLS11,
-					VersionTLS10}},
-				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{
+				}},
+				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{ //signature_algorithms
 					ECDSAWithP256AndSHA256,
 					ECDSAWithP384AndSHA384,
 					ECDSAWithP521AndSHA512,
@@ -399,9 +859,11 @@ func utlsIdToSpec(id ClientHelloID) (ClientHelloSpec, error) {
 					ECDSAWithSHA1,
 					PKCS1WithSHA1,
 				}},
-				&PSKKeyExchangeModesExtension{[]uint8{pskModeDHE}},
-				&FakeRecordSizeLimitExtension{0x4001},
-				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle},
+				&PSKKeyExchangeModesExtension{[]uint8{ //psk_key_exchange_modes
+					PskModeDHE,
+				}},
+				&FakeRecordSizeLimitExtension{Limit: 0x4001},             //record_size_limit
+				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle}, //padding
 			}}, nil
 	case HelloIOS_11_1:
 		return ClientHelloSpec{
@@ -524,6 +986,214 @@ func utlsIdToSpec(id ClientHelloID) (ClientHelloSpec, error) {
 				}},
 			},
 		}, nil
+	case HelloIOS_13:
+		return ClientHelloSpec{
+			CipherSuites: []uint16{
+				TLS_AES_128_GCM_SHA256,
+				TLS_AES_256_GCM_SHA384,
+				TLS_CHACHA20_POLY1305_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+				DISABLED_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384,
+				TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+				TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
+				TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+				DISABLED_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384,
+				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
+				TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+				TLS_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_RSA_WITH_AES_128_GCM_SHA256,
+				DISABLED_TLS_RSA_WITH_AES_256_CBC_SHA256,
+				TLS_RSA_WITH_AES_128_CBC_SHA256,
+				TLS_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_AES_128_CBC_SHA,
+				0xc008,
+				TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
+				TLS_RSA_WITH_3DES_EDE_CBC_SHA,
+			},
+			CompressionMethods: []byte{
+				0x00, // compressionNone
+			},
+			Extensions: []TLSExtension{
+				&RenegotiationInfoExtension{Renegotiation: RenegotiateOnceAsClient},
+				&SNIExtension{},
+				&UtlsExtendedMasterSecretExtension{},
+				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{
+					ECDSAWithP256AndSHA256,
+					PSSWithSHA256,
+					PKCS1WithSHA256,
+					ECDSAWithP384AndSHA384,
+					ECDSAWithSHA1,
+					PSSWithSHA384,
+					PSSWithSHA384,
+					PKCS1WithSHA384,
+					PSSWithSHA512,
+					PKCS1WithSHA512,
+					PKCS1WithSHA1,
+				}},
+				&StatusRequestExtension{},
+				&SCTExtension{},
+				&ALPNExtension{AlpnProtocols: []string{"h2", "http/1.1"}},
+				&SupportedPointsExtension{SupportedPoints: []byte{
+					0x00, // pointFormatUncompressed
+				}},
+				&KeyShareExtension{[]KeyShare{
+					{Group: X25519},
+				}},
+				&PSKKeyExchangeModesExtension{[]uint8{
+					PskModeDHE,
+				}},
+				&SupportedVersionsExtension{[]uint16{
+					VersionTLS13,
+					VersionTLS12,
+					VersionTLS11,
+					VersionTLS10,
+				}},
+				&SupportedCurvesExtension{[]CurveID{
+					X25519,
+					CurveP256,
+					CurveP384,
+					CurveP521,
+				}},
+				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle},
+			},
+		}, nil
+	case HelloIOS_14:
+		return ClientHelloSpec{
+			// TLSVersMax: VersionTLS12,
+			// TLSVersMin: VersionTLS10,
+			CipherSuites: []uint16{
+				GREASE_PLACEHOLDER,
+				TLS_AES_128_GCM_SHA256,
+				TLS_AES_256_GCM_SHA384,
+				TLS_CHACHA20_POLY1305_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+				TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+				DISABLED_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384,
+				TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+				TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
+				DISABLED_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384,
+				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
+				TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+				TLS_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_RSA_WITH_AES_128_GCM_SHA256,
+				DISABLED_TLS_RSA_WITH_AES_256_CBC_SHA256,
+				TLS_RSA_WITH_AES_128_CBC_SHA256,
+				TLS_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_AES_128_CBC_SHA,
+				0xc008,
+				TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
+				TLS_RSA_WITH_3DES_EDE_CBC_SHA,
+			},
+			CompressionMethods: []byte{
+				0x00, // compressionNone
+			},
+			Extensions: []TLSExtension{
+				&UtlsGREASEExtension{},
+				&SNIExtension{},
+				&UtlsExtendedMasterSecretExtension{},
+				&RenegotiationInfoExtension{Renegotiation: RenegotiateOnceAsClient},
+				&SupportedCurvesExtension{[]CurveID{
+					CurveID(GREASE_PLACEHOLDER),
+					X25519,
+					CurveP256,
+					CurveP384,
+					CurveP521,
+				}},
+				&SupportedPointsExtension{SupportedPoints: []byte{
+					0x00, // pointFormatUncompressed
+				}},
+				&ALPNExtension{AlpnProtocols: []string{"h2", "http/1.1"}},
+				&StatusRequestExtension{},
+				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{
+					ECDSAWithP256AndSHA256,
+					PSSWithSHA256,
+					PKCS1WithSHA256,
+					ECDSAWithP384AndSHA384,
+					ECDSAWithSHA1,
+					PSSWithSHA384,
+					PSSWithSHA384,
+					PKCS1WithSHA384,
+					PSSWithSHA512,
+					PKCS1WithSHA512,
+					PKCS1WithSHA1,
+				}},
+				&SCTExtension{},
+				&KeyShareExtension{[]KeyShare{
+					{Group: CurveID(GREASE_PLACEHOLDER), Data: []byte{0}},
+					{Group: X25519},
+				}},
+				&PSKKeyExchangeModesExtension{[]uint8{
+					PskModeDHE,
+				}},
+				&SupportedVersionsExtension{[]uint16{
+					GREASE_PLACEHOLDER,
+					VersionTLS13,
+					VersionTLS12,
+					VersionTLS11,
+					VersionTLS10,
+				}},
+				&UtlsGREASEExtension{},
+				&UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle},
+			},
+		}, nil
+	case HelloAndroid_11_OkHttp:
+		return ClientHelloSpec{
+			CipherSuites: []uint16{
+				TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+				0xcca9, // Cipher Suite: TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 (0xcca9)
+				TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+				0xcca8, // Cipher Suite: TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 (0xcca8)
+				TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+				TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				TLS_RSA_WITH_AES_128_GCM_SHA256,
+				TLS_RSA_WITH_AES_256_GCM_SHA384,
+				TLS_RSA_WITH_AES_128_CBC_SHA,
+				TLS_RSA_WITH_AES_256_CBC_SHA,
+			},
+			CompressionMethods: []byte{
+				0x00, // compressionNone
+			},
+			Extensions: []TLSExtension{
+				&SNIExtension{},
+				&UtlsExtendedMasterSecretExtension{},
+				&RenegotiationInfoExtension{},
+				// supported_groups
+				&SupportedCurvesExtension{[]CurveID{
+					X25519,
+					CurveP256,
+					CurveP384,
+				}},
+				&SupportedPointsExtension{SupportedPoints: []byte{
+					0x00, // pointFormatUncompressed
+				}},
+				&StatusRequestExtension{},
+				&SignatureAlgorithmsExtension{SupportedSignatureAlgorithms: []SignatureScheme{
+					ECDSAWithP256AndSHA256,
+					PSSWithSHA256,
+					PKCS1WithSHA256,
+					ECDSAWithP384AndSHA384,
+					PSSWithSHA384,
+					PKCS1WithSHA384,
+					PSSWithSHA512,
+					PKCS1WithSHA512,
+					PKCS1WithSHA1,
+				}},
+			},
+		}, nil
 	default:
 		return ClientHelloSpec{}, errors.New("ClientHello ID " + id.Str() + " is unknown")
 	}
@@ -858,6 +1528,32 @@ func (uconn *UConn) generateRandomizedSpec() (ClientHelloSpec, error) {
 			Versions: makeSupportedVersions(p.TLSVersMin, p.TLSVersMax),
 		}
 		p.Extensions = append(p.Extensions, &ks, &pskExchangeModes, &supportedVersionsExt)
+
+		// Randomly add an ALPS extension. ALPS is TLS 1.3-only and may only
+		// appear when an ALPN extension is present
+		// (https://datatracker.ietf.org/doc/html/draft-vvv-tls-alps-01#section-3).
+		// ALPS is a draft specification at this time, but appears in
+		// Chrome/BoringSSL.
+		if WithALPN {
+
+			// ALPS is a new addition to generateRandomizedSpec. Use a salted
+			// seed to create a new, independent PRNG, so that a seed used
+			// with the previous version of generateRandomizedSpec will
+			// produce the exact same spec as long as ALPS isn't selected.
+			r, err := newPRNGWithSaltedSeed(uconn.ClientHelloID.Seed, "ALPS")
+			if err != nil {
+				return p, err
+			}
+			if r.FlipWeightedCoin(0.33) {
+				// As with the ALPN case above, default to something popular
+				// (unlike ALPN, ALPS can't yet be specified in uconn.config).
+				alps := &ApplicationSettingsExtension{SupportedProtocols: []string{"h2"}}
+				p.Extensions = append(p.Extensions, alps)
+			}
+		}
+
+		// TODO: randomly add DelegatedCredentialsExtension, once it is
+		// sufficiently popular.
 	}
 	r.rand.Shuffle(len(p.Extensions), func(i, j int) {
 		p.Extensions[i], p.Extensions[j] = p.Extensions[j], p.Extensions[i]
diff --git a/u_prng.go b/u_prng.go
index 9a30cd7f..e00ab6f0 100644
--- a/u_prng.go
+++ b/u_prng.go
@@ -19,6 +19,7 @@ import (
 	"math/rand"
 	"sync"
 
+	"golang.org/x/crypto/hkdf"
 	"golang.org/x/crypto/sha3"
 )
 
@@ -39,6 +40,21 @@ func NewPRNGSeed() (*PRNGSeed, error) {
 	return seed, nil
 }
 
+// newSaltedPRNGSeed creates a new seed derived from an existing seed and a
+// salt. A HKDF is applied to the seed and salt.
+//
+// newSaltedPRNGSeed is intended for use cases where a single seed needs to be
+// used in distinct contexts to produce independent random streams.
+func newSaltedPRNGSeed(seed *PRNGSeed, salt string) (*PRNGSeed, error) {
+	saltedSeed := new(PRNGSeed)
+	_, err := io.ReadFull(
+		hkdf.New(sha3.New256, seed[:], []byte(salt), nil), saltedSeed[:])
+	if err != nil {
+		return nil, err
+	}
+	return saltedSeed, nil
+}
+
 // prng is a seeded, unbiased PRNG based on SHAKE256. that is suitable for use
 // cases such as obfuscation. Seeding is based on crypto/rand.Read.
 //
@@ -78,6 +94,16 @@ func newPRNGWithSeed(seed *PRNGSeed) (*prng, error) {
 	return p, nil
 }
 
+// newPRNGWithSaltedSeed initializes a new PRNG using a seed derived from an
+// existing seed and a salt with NewSaltedSeed.
+func newPRNGWithSaltedSeed(seed *PRNGSeed, salt string) (*prng, error) {
+	saltedSeed, err := newSaltedPRNGSeed(seed, salt)
+	if err != nil {
+		return nil, err
+	}
+	return newPRNGWithSeed(saltedSeed)
+}
+
 // Read reads random bytes from the PRNG stream into b. Read conforms to
 // io.Reader and always returns len(p), nil.
 func (p *prng) Read(b []byte) (int, error) {
diff --git a/u_tls_extensions.go b/u_tls_extensions.go
index 8bf4f4b0..3e878753 100644
--- a/u_tls_extensions.go
+++ b/u_tls_extensions.go
@@ -79,7 +79,7 @@ func (e *SNIExtension) Read(b []byte) (int, error) {
 	b[0] = byte(extensionServerName >> 8)
 	b[1] = byte(extensionServerName)
 	b[2] = byte((len(hostName) + 5) >> 8)
-	b[3] = byte((len(hostName) + 5))
+	b[3] = byte(len(hostName) + 5)
 	b[4] = byte((len(hostName) + 3) >> 8)
 	b[5] = byte(len(hostName) + 3)
 	// b[6] Server Name Type: host_name (0)
@@ -115,6 +115,36 @@ func (e *StatusRequestExtension) Read(b []byte) (int, error) {
 	return e.Len(), io.EOF
 }
 
+type StatusRequestV2Extension struct {
+}
+
+func (e *StatusRequestV2Extension) writeToUConn(uc *UConn) error {
+	uc.HandshakeState.Hello.OcspStapling = true
+	return nil
+}
+
+func (e *StatusRequestV2Extension) Len() int {
+	return 13
+}
+
+func (e *StatusRequestV2Extension) Read(b []byte) (int, error) {
+	if len(b) < e.Len() {
+		return 0, io.ErrShortBuffer
+	}
+	// RFC 4366, section 3.6
+	b[0] = byte(17 >> 8)
+	b[1] = byte(17)
+	b[2] = 0
+	b[3] = 9
+	b[4] = 0
+	b[5] = 7
+	b[6] = 2 // OCSP type
+	b[7] = 0
+	b[8] = 4
+	// Two zero valued uint16s for the two lengths.
+	return e.Len(), io.EOF
+}
+
 type SupportedCurvesExtension struct {
 	Curves []CurveID
 }
@@ -137,9 +167,9 @@ func (e *SupportedCurvesExtension) Read(b []byte) (int, error) {
 	b[0] = byte(extensionSupportedCurves >> 8)
 	b[1] = byte(extensionSupportedCurves)
 	b[2] = byte((2 + 2*len(e.Curves)) >> 8)
-	b[3] = byte((2 + 2*len(e.Curves)))
+	b[3] = byte(2 + 2*len(e.Curves))
 	b[4] = byte((2 * len(e.Curves)) >> 8)
-	b[5] = byte((2 * len(e.Curves)))
+	b[5] = byte(2 * len(e.Curves))
 	for i, curve := range e.Curves {
 		b[6+2*i] = byte(curve >> 8)
 		b[7+2*i] = byte(curve)
@@ -168,8 +198,8 @@ func (e *SupportedPointsExtension) Read(b []byte) (int, error) {
 	b[0] = byte(extensionSupportedPoints >> 8)
 	b[1] = byte(extensionSupportedPoints)
 	b[2] = byte((1 + len(e.SupportedPoints)) >> 8)
-	b[3] = byte((1 + len(e.SupportedPoints)))
-	b[4] = byte((len(e.SupportedPoints)))
+	b[3] = byte(1 + len(e.SupportedPoints))
+	b[4] = byte(len(e.SupportedPoints))
 	for i, pointFormat := range e.SupportedPoints {
 		b[5+i] = pointFormat
 	}
@@ -197,9 +227,40 @@ func (e *SignatureAlgorithmsExtension) Read(b []byte) (int, error) {
 	b[0] = byte(extensionSignatureAlgorithms >> 8)
 	b[1] = byte(extensionSignatureAlgorithms)
 	b[2] = byte((2 + 2*len(e.SupportedSignatureAlgorithms)) >> 8)
-	b[3] = byte((2 + 2*len(e.SupportedSignatureAlgorithms)))
+	b[3] = byte(2 + 2*len(e.SupportedSignatureAlgorithms))
+	b[4] = byte((2 * len(e.SupportedSignatureAlgorithms)) >> 8)
+	b[5] = byte(2 * len(e.SupportedSignatureAlgorithms))
+	for i, sigAndHash := range e.SupportedSignatureAlgorithms {
+		b[6+2*i] = byte(sigAndHash >> 8)
+		b[7+2*i] = byte(sigAndHash)
+	}
+	return e.Len(), io.EOF
+}
+
+type SignatureAlgorithmsCertExtension struct {
+	SupportedSignatureAlgorithms []SignatureScheme
+}
+
+func (e *SignatureAlgorithmsCertExtension) writeToUConn(uc *UConn) error {
+	uc.HandshakeState.Hello.SupportedSignatureAlgorithms = e.SupportedSignatureAlgorithms
+	return nil
+}
+
+func (e *SignatureAlgorithmsCertExtension) Len() int {
+	return 6 + 2*len(e.SupportedSignatureAlgorithms)
+}
+
+func (e *SignatureAlgorithmsCertExtension) Read(b []byte) (int, error) {
+	if len(b) < e.Len() {
+		return 0, io.ErrShortBuffer
+	}
+	// https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1
+	b[0] = byte(extensionSignatureAlgorithmsCert >> 8)
+	b[1] = byte(extensionSignatureAlgorithmsCert)
+	b[2] = byte((2 + 2*len(e.SupportedSignatureAlgorithms)) >> 8)
+	b[3] = byte(2 + 2*len(e.SupportedSignatureAlgorithms))
 	b[4] = byte((2 * len(e.SupportedSignatureAlgorithms)) >> 8)
-	b[5] = byte((2 * len(e.SupportedSignatureAlgorithms)))
+	b[5] = byte(2 * len(e.SupportedSignatureAlgorithms))
 	for i, sigAndHash := range e.SupportedSignatureAlgorithms {
 		b[6+2*i] = byte(sigAndHash >> 8)
 		b[7+2*i] = byte(sigAndHash)
@@ -295,6 +356,52 @@ func (e *ALPNExtension) Read(b []byte) (int, error) {
 	return e.Len(), io.EOF
 }
 
+type ApplicationSettingsExtension struct {
+	SupportedProtocols []string
+}
+
+func (e *ApplicationSettingsExtension) writeToUConn(uc *UConn) error {
+	return nil
+}
+
+func (e *ApplicationSettingsExtension) Len() int {
+	bLen := 2 + 2 + 2 // Type + Length + ALPS Extension length
+	for _, s := range e.SupportedProtocols {
+		bLen += 1 + len(s) // Supported ALPN Length + actual length of protocol
+	}
+	return bLen
+}
+
+func (e *ApplicationSettingsExtension) Read(b []byte) (int, error) {
+	if len(b) < e.Len() {
+		return 0, io.ErrShortBuffer
+	}
+
+	// Read Type.
+	b[0] = byte(extensionALPS >> 8)   // hex: 44 dec: 68
+	b[1] = byte(extensionALPS & 0xff) // hex: 69 dec: 105
+
+	lengths := b[2:] // get the remaining buffer without Type
+	b = b[6:]        // set the buffer to the buffer without Type, Length and ALPS Extension Length (so only the Supported ALPN list remains)
+
+	stringsLength := 0
+	for _, s := range e.SupportedProtocols {
+		l := len(s)            // Supported ALPN Length
+		b[0] = byte(l)         // Supported ALPN Length in bytes hex: 02 dec: 2
+		copy(b[1:], s)         // copy the Supported ALPN as bytes to the buffer
+		b = b[1+l:]            // set the buffer to the buffer without the Supported ALPN Length and Supported ALPN (so we can continue to the next protocol in this loop)
+		stringsLength += 1 + l // Supported ALPN Length (the field itself) + Supported ALPN Length (the value)
+	}
+
+	lengths[2] = byte(stringsLength >> 8) // ALPS Extension Length hex: 00 dec: 0
+	lengths[3] = byte(stringsLength)      // ALPS Extension Length hex: 03 dec: 3
+	stringsLength += 2                    // plus ALPS Extension Length field length
+	lengths[0] = byte(stringsLength >> 8) // Length hex:00 dec: 0
+	lengths[1] = byte(stringsLength)      // Length hex: 05 dec: 5
+
+	return e.Len(), io.EOF
+}
+
 type SCTExtension struct {
 }
 
@@ -598,9 +705,9 @@ func (e *KeyShareExtension) Read(b []byte) (int, error) {
 	b[1] = byte(extensionKeyShare)
 	keySharesLen := e.keySharesLen()
 	b[2] = byte((keySharesLen + 2) >> 8)
-	b[3] = byte((keySharesLen + 2))
+	b[3] = byte(keySharesLen + 2)
 	b[4] = byte((keySharesLen) >> 8)
-	b[5] = byte((keySharesLen))
+	b[5] = byte(keySharesLen)
 
 	i := 6
 	for _, ks := range e.KeyShares {
@@ -642,7 +749,7 @@ func (e *PSKKeyExchangeModesExtension) Read(b []byte) (int, error) {
 
 	modesLen := len(e.Modes)
 	b[2] = byte((modesLen + 1) >> 8)
-	b[3] = byte((modesLen + 1))
+	b[3] = byte(modesLen + 1)
 	b[4] = byte(modesLen)
 
 	if len(e.Modes) > 0 {
@@ -682,7 +789,7 @@ func (e *SupportedVersionsExtension) Read(b []byte) (int, error) {
 	b[0] = byte(extensionSupportedVersions >> 8)
 	b[1] = byte(extensionSupportedVersions)
 	b[2] = byte((extLen + 1) >> 8)
-	b[3] = byte((extLen + 1))
+	b[3] = byte(extLen + 1)
 	b[4] = byte(extLen)
 
 	i := 5
@@ -775,3 +882,32 @@ func (e *FakeRecordSizeLimitExtension) Read(b []byte) (int, error) {
 	b[5] = byte(e.Limit & 0xff)
 	return e.Len(), io.EOF
 }
+
+type DelegatedCredentialsExtension struct {
+	AlgorithmsSignature []SignatureScheme
+}
+
+func (e *DelegatedCredentialsExtension) writeToUConn(uc *UConn) error {
+	return nil
+}
+
+func (e *DelegatedCredentialsExtension) Len() int {
+	return 6 + 2*len(e.AlgorithmsSignature)
+}
+
+func (e *DelegatedCredentialsExtension) Read(b []byte) (int, error) {
+	if len(b) < e.Len() {
+		return 0, io.ErrShortBuffer
+	}
+	b[0] = byte(extensionDelegatedCredentials >> 8)
+	b[1] = byte(extensionDelegatedCredentials)
+	b[2] = byte((2 + 2*len(e.AlgorithmsSignature)) >> 8)
+	b[3] = byte(2 + 2*len(e.AlgorithmsSignature))
+	b[4] = byte((2 * len(e.AlgorithmsSignature)) >> 8)
+	b[5] = byte(2 * len(e.AlgorithmsSignature))
+	for i, sigAndHash := range e.AlgorithmsSignature {
+		b[6+2*i] = byte(sigAndHash >> 8)
+		b[7+2*i] = byte(sigAndHash)
+	}
+	return e.Len(), io.EOF
+}