diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe8968a..b1311e6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Added
+
+- Handle `--data-ciphers` and `data-ciphers-fallback` from OpenVPN 2.5
+
 ## 3.2.0 (2021-01-07)
 
 ### Changed
diff --git a/TunnelKit/Sources/Protocols/OpenVPN/Authenticator.swift b/TunnelKit/Sources/Protocols/OpenVPN/Authenticator.swift
index d6a6452..ec1eb20 100644
--- a/TunnelKit/Sources/Protocols/OpenVPN/Authenticator.swift
+++ b/TunnelKit/Sources/Protocols/OpenVPN/Authenticator.swift
@@ -156,7 +156,11 @@ extension OpenVPN {
             }
 
             // peer info
-            raw.appendSized(Z(CoreConfiguration.OpenVPN.peerInfo, nullTerminated: true))
+            var extra: [String: String] = [:]
+            if let dataCiphers = options.dataCiphers {
+                extra["IV_CIPHERS"] = dataCiphers.map { $0.rawValue }.joined(separator: ":")
+            }
+            raw.appendSized(Z(CoreConfiguration.OpenVPN.peerInfo(extra: extra), nullTerminated: true))
 
             if CoreConfiguration.logsSensitiveData {
                 log.debug("TLS.auth: Put plaintext (\(raw.count) bytes): \(raw.toHex())")
diff --git a/TunnelKit/Sources/Protocols/OpenVPN/Configuration.swift b/TunnelKit/Sources/Protocols/OpenVPN/Configuration.swift
index 3b94188..26cd931 100644
--- a/TunnelKit/Sources/Protocols/OpenVPN/Configuration.swift
+++ b/TunnelKit/Sources/Protocols/OpenVPN/Configuration.swift
@@ -178,6 +178,9 @@ extension OpenVPN {
         /// The cipher algorithm for data encryption.
         public var cipher: Cipher?
         
+        /// The set of supported cipher algorithms for data encryption (2.5.).
+        public var dataCiphers: [Cipher]?
+        
         /// The digest algorithm for HMAC.
         public var digest: Digest?
         
@@ -298,6 +301,7 @@ extension OpenVPN {
         public func build() -> Configuration {
             return Configuration(
                 cipher: cipher,
+                dataCiphers: dataCiphers,
                 digest: digest,
                 compressionFraming: compressionFraming,
                 compressionAlgorithm: compressionAlgorithm,
@@ -355,6 +359,9 @@ extension OpenVPN {
         /// - Seealso: `ConfigurationBuilder.cipher`
         public let cipher: Cipher?
         
+        /// - Seealso: `ConfigurationBuilder.dataCiphers`
+        public let dataCiphers: [Cipher]?
+        
         /// - Seealso: `ConfigurationBuilder.digest`
         public let digest: Digest?
         
@@ -476,6 +483,7 @@ extension OpenVPN.Configuration {
     public func builder() -> OpenVPN.ConfigurationBuilder {
         var builder = OpenVPN.ConfigurationBuilder()
         builder.cipher = cipher
+        builder.dataCiphers = dataCiphers
         builder.digest = digest
         builder.compressionFraming = compressionFraming
         builder.compressionAlgorithm = compressionAlgorithm
diff --git a/TunnelKit/Sources/Protocols/OpenVPN/ConfigurationParser.swift b/TunnelKit/Sources/Protocols/OpenVPN/ConfigurationParser.swift
index 6a15ae7..8c1895e 100644
--- a/TunnelKit/Sources/Protocols/OpenVPN/ConfigurationParser.swift
+++ b/TunnelKit/Sources/Protocols/OpenVPN/ConfigurationParser.swift
@@ -42,6 +42,10 @@ extension OpenVPN {
             
             static let cipher = NSRegularExpression("^cipher +[^,\\s]+")
             
+            static let dataCiphers = NSRegularExpression("^(data-ciphers|ncp-ciphers) +[^,\\s]+(:[^,\\s]+)*")
+            
+            static let dataCiphersFallback = NSRegularExpression("^data-ciphers-fallback +[^,\\s]+")
+            
             static let auth = NSRegularExpression("^auth +[\\w\\-]+")
             
             static let compLZO = NSRegularExpression("^comp-lzo.*")
@@ -199,6 +203,8 @@ extension OpenVPN {
             var currentBlockName: String?
             var currentBlock: [String] = []
             
+            var optDataCiphers: [Cipher]?
+            var optDataCiphersFallback: Cipher?
             var optCipher: Cipher?
             var optDigest: Digest?
             var optCompressionFraming: CompressionFraming?
@@ -345,9 +351,27 @@ extension OpenVPN {
                         return
                     }
                     optCipher = Cipher(rawValue: rawValue.uppercased())
-                    if optCipher == nil {
-                        unsupportedError = ConfigurationError.unsupportedConfiguration(option: "cipher \(rawValue)")
+                }
+                Regex.dataCiphers.enumerateArguments(in: line) {
+                    isHandled = true
+                    guard let rawValue = $0.first else {
+                        return
                     }
+                    let rawCiphers = rawValue.components(separatedBy: ":")
+                    optDataCiphers = []
+                    rawCiphers.forEach {
+                        guard let cipher = Cipher(rawValue: $0.uppercased()) else {
+                            return
+                        }
+                        optDataCiphers?.append(cipher)
+                    }
+                }
+                Regex.dataCiphersFallback.enumerateArguments(in: line) {
+                    isHandled = true
+                    guard let rawValue = $0.first else {
+                        return
+                    }
+                    optDataCiphersFallback = Cipher(rawValue: rawValue.uppercased())
                 }
                 Regex.auth.enumerateArguments(in: line) {
                     isHandled = true
@@ -610,8 +634,8 @@ extension OpenVPN {
                 guard let _ = optCA else {
                     throw ConfigurationError.missingConfiguration(option: "ca")
                 }
-                guard let _ = optCipher else {
-                    throw ConfigurationError.missingConfiguration(option: "cipher")
+                guard optCipher != nil || !(optDataCiphers?.isEmpty ?? false) else {
+                    throw ConfigurationError.missingConfiguration(option: "cipher or data-ciphers")
                 }
             }
             
@@ -621,7 +645,8 @@ extension OpenVPN {
             
             // MARK: General
             
-            sessionBuilder.cipher = optCipher
+            sessionBuilder.cipher = optDataCiphersFallback ?? optCipher
+            sessionBuilder.dataCiphers = optDataCiphers
             sessionBuilder.digest = optDigest
             sessionBuilder.compressionFraming = optCompressionFraming
             sessionBuilder.compressionAlgorithm = optCompressionAlgorithm
diff --git a/TunnelKit/Sources/Protocols/OpenVPN/CoreConfiguration+OpenVPN.swift b/TunnelKit/Sources/Protocols/OpenVPN/CoreConfiguration+OpenVPN.swift
index bda07e1..2c45335 100644
--- a/TunnelKit/Sources/Protocols/OpenVPN/CoreConfiguration+OpenVPN.swift
+++ b/TunnelKit/Sources/Protocols/OpenVPN/CoreConfiguration+OpenVPN.swift
@@ -63,7 +63,7 @@ extension CoreConfiguration {
         
         // MARK: Authentication
         
-        static let peerInfo: String = {
+        static func peerInfo(extra: [String: String]? = nil) -> String {
             let platform: String
             #if os(iOS)
             platform = "ios"
@@ -83,9 +83,12 @@ extension CoreConfiguration {
             if LZOIsSupported() {
                 info.append("IV_LZO=1")
             }
+            if let extra = extra {
+                info.append(contentsOf: extra.map { "\($0)=\($1)" })
+            }
             info.append("")
             return info.joined(separator: "\n")
-        }()
+        }
         
         static let randomLength = 32