diff --git a/.gitignore b/.gitignore
index 0672057c36..ba6dd8df33 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,7 +11,6 @@ tags
 
 .gradle
 local.properties
-/docs/build/doctrees
 
 # General build files
 **/build/*
@@ -34,7 +33,6 @@ lib/dokka.jar
 .idea/libraries
 .idea/shelf
 .idea/dataSources
-.idea/modules.xml
 
 # if you remove the above rule, at least ignore the following:
 
diff --git a/core/src/main/kotlin/net/corda/core/contracts/TransactionTypes.kt b/core/src/main/kotlin/net/corda/core/contracts/TransactionTypes.kt
index 3570bc35e1..7cd6ef4d39 100644
--- a/core/src/main/kotlin/net/corda/core/contracts/TransactionTypes.kt
+++ b/core/src/main/kotlin/net/corda/core/contracts/TransactionTypes.kt
@@ -17,6 +17,7 @@ sealed class TransactionType {
      *
      * Note: Presence of _signatures_ is not checked, only the public keys to be signed for.
      */
+    @Throws(TransactionVerificationException::class)
     fun verify(tx: LedgerTransaction) {
         require(tx.notary != null || tx.timestamp == null) { "Transactions with timestamps must be notarised." }
         val duplicates = detectDuplicateInputs(tx)
diff --git a/core/src/main/kotlin/net/corda/core/contracts/TransactionVerification.kt b/core/src/main/kotlin/net/corda/core/contracts/TransactionVerification.kt
index 060d8c49f5..2c59c872f9 100644
--- a/core/src/main/kotlin/net/corda/core/contracts/TransactionVerification.kt
+++ b/core/src/main/kotlin/net/corda/core/contracts/TransactionVerification.kt
@@ -3,6 +3,7 @@ package net.corda.core.contracts
 import net.corda.core.crypto.CompositeKey
 import net.corda.core.crypto.Party
 import net.corda.core.crypto.SecureHash
+import net.corda.core.flows.FlowException
 import net.corda.core.transactions.LedgerTransaction
 import java.util.*
 
@@ -85,30 +86,35 @@ data class TransactionForContract(val inputs: List<ContractState>,
     data class InOutGroup<out T : ContractState, out K : Any>(val inputs: List<T>, val outputs: List<T>, val groupingKey: K)
 }
 
-class TransactionResolutionException(val hash: SecureHash) : Exception() {
-    override fun toString() = "Transaction resolution failure for $hash"
+class TransactionResolutionException(val hash: SecureHash) : FlowException() {
+    override fun toString(): String = "Transaction resolution failure for $hash"
+}
+
+class AttachmentResolutionException(val hash : SecureHash) : FlowException() {
+    override fun toString(): String = "Attachment resolution failure for $hash"
 }
 
 class TransactionConflictException(val conflictRef: StateRef, val tx1: LedgerTransaction, val tx2: LedgerTransaction) : Exception()
 
-sealed class TransactionVerificationException(val tx: LedgerTransaction, cause: Throwable?) : Exception(cause) {
+sealed class TransactionVerificationException(val tx: LedgerTransaction, cause: Throwable?) : FlowException(cause) {
     class ContractRejection(tx: LedgerTransaction, val contract: Contract, cause: Throwable?) : TransactionVerificationException(tx, cause)
     class MoreThanOneNotary(tx: LedgerTransaction) : TransactionVerificationException(tx, null)
     class SignersMissing(tx: LedgerTransaction, val missing: List<CompositeKey>) : TransactionVerificationException(tx, null) {
-        override fun toString() = "Signers missing: ${missing.joinToString()}"
+        override fun toString(): String = "Signers missing: ${missing.joinToString()}"
     }
     class DuplicateInputStates(tx: LedgerTransaction, val duplicates: Set<StateRef>) : TransactionVerificationException(tx, null) {
-        override fun toString() = "Duplicate inputs: ${duplicates.joinToString()}"
+        override fun toString(): String = "Duplicate inputs: ${duplicates.joinToString()}"
     }
 
     class InvalidNotaryChange(tx: LedgerTransaction) : TransactionVerificationException(tx, null)
     class NotaryChangeInWrongTransactionType(tx: LedgerTransaction, val outputNotary: Party) : TransactionVerificationException(tx, null) {
-        override fun toString(): String = "Found unexpected notary change in transaction. Tx notary: ${tx.notary}, found: ${outputNotary}"
+        override fun toString(): String {
+            return "Found unexpected notary change in transaction. Tx notary: ${tx.notary}, found: $outputNotary"
+        }
     }
 
     class TransactionMissingEncumbranceException(tx: LedgerTransaction, val missing: Int, val inOut: Direction) : TransactionVerificationException(tx, null) {
-        override val message: String?
-            get() = "Missing required encumbrance ${missing} in ${inOut}"
+        override val message: String get() = "Missing required encumbrance $missing in $inOut"
     }
     enum class Direction {
         INPUT,
diff --git a/core/src/main/kotlin/net/corda/core/flows/FlowException.kt b/core/src/main/kotlin/net/corda/core/flows/FlowException.kt
index fc8014f4d4..9419049d68 100644
--- a/core/src/main/kotlin/net/corda/core/flows/FlowException.kt
+++ b/core/src/main/kotlin/net/corda/core/flows/FlowException.kt
@@ -9,5 +9,8 @@ package net.corda.core.flows
  * [FlowException] (or a subclass) can be a valid expected response from a flow, particularly ones which act as a service.
  * It is recommended a [FlowLogic] document the [FlowException] types it can throw.
  */
-open class FlowException @JvmOverloads constructor(message: String? = null, cause: Throwable? = null)
-    : Exception(message, cause)
+open class FlowException(override val message: String?, override val cause: Throwable?) : Exception() {
+    constructor(message: String?) : this(message, null)
+    constructor(cause: Throwable?) : this(cause?.toString(), cause)
+    constructor() : this(null, null)
+}
diff --git a/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt b/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt
index 26c44f711f..4a548c0c46 100644
--- a/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt
+++ b/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt
@@ -54,6 +54,7 @@ class LedgerTransaction(
      *
      * @throws TransactionVerificationException if anything goes wrong.
      */
+    @Throws(TransactionVerificationException::class)
     fun verify() = type.verify(this)
 
     // TODO: When we upgrade to Kotlin 1.1 we can make this a data class again and have the compiler generate these.
diff --git a/core/src/main/kotlin/net/corda/core/transactions/SignedTransaction.kt b/core/src/main/kotlin/net/corda/core/transactions/SignedTransaction.kt
index efde6949fd..49349f0882 100644
--- a/core/src/main/kotlin/net/corda/core/transactions/SignedTransaction.kt
+++ b/core/src/main/kotlin/net/corda/core/transactions/SignedTransaction.kt
@@ -1,5 +1,6 @@
 package net.corda.core.transactions
 
+import net.corda.core.contracts.AttachmentResolutionException
 import net.corda.core.contracts.NamedByHash
 import net.corda.core.contracts.TransactionResolutionException
 import net.corda.core.crypto.CompositeKey
@@ -8,7 +9,6 @@ import net.corda.core.crypto.SecureHash
 import net.corda.core.crypto.signWithECDSA
 import net.corda.core.node.ServiceHub
 import net.corda.core.serialization.SerializedBytes
-import java.io.FileNotFoundException
 import java.security.KeyPair
 import java.security.SignatureException
 import java.util.*
@@ -127,12 +127,12 @@ data class SignedTransaction(val txBits: SerializedBytes<WireTransaction>,
      * [WireTransaction.toLedgerTransaction] with the passed in [ServiceHub] to resolve the dependencies,
      * returning an unverified LedgerTransaction.
      *
-     * @throws FileNotFoundException if a required attachment was not found in storage.
+     * @throws AttachmentResolutionException if a required attachment was not found in storage.
      * @throws TransactionResolutionException if an input points to a transaction not found in storage.
      * @throws SignatureException if any signatures were invalid or unrecognised
      * @throws SignaturesMissingException if any signatures that should have been present are missing.
      */
-    @Throws(FileNotFoundException::class, TransactionResolutionException::class, SignaturesMissingException::class)
+    @Throws(AttachmentResolutionException::class, TransactionResolutionException::class, SignatureException::class)
     fun toLedgerTransaction(services: ServiceHub) = verifySignatures().toLedgerTransaction(services)
 
     /**
diff --git a/core/src/main/kotlin/net/corda/core/transactions/WireTransaction.kt b/core/src/main/kotlin/net/corda/core/transactions/WireTransaction.kt
index 1a8a40ab04..583448f518 100644
--- a/core/src/main/kotlin/net/corda/core/transactions/WireTransaction.kt
+++ b/core/src/main/kotlin/net/corda/core/transactions/WireTransaction.kt
@@ -12,7 +12,6 @@ import net.corda.core.serialization.THREAD_LOCAL_KRYO
 import net.corda.core.serialization.deserialize
 import net.corda.core.serialization.serialize
 import net.corda.core.utilities.Emoji
-import java.io.FileNotFoundException
 import java.security.PublicKey
 
 /**
@@ -66,10 +65,10 @@ class WireTransaction(
      * Looks up identities and attachments from storage to generate a [LedgerTransaction]. A transaction is expected to
      * have been fully resolved using the resolution flow by this point.
      *
-     * @throws FileNotFoundException if a required attachment was not found in storage.
+     * @throws AttachmentResolutionException if a required attachment was not found in storage.
      * @throws TransactionResolutionException if an input points to a transaction not found in storage.
      */
-    @Throws(FileNotFoundException::class, TransactionResolutionException::class)
+    @Throws(AttachmentResolutionException::class, TransactionResolutionException::class)
     fun toLedgerTransaction(services: ServiceHub): LedgerTransaction {
         // Look up public keys to authenticated identities. This is just a stub placeholder and will all change in future.
         val authenticatedArgs = commands.map {
@@ -78,7 +77,7 @@ class WireTransaction(
         }
         // Open attachments specified in this transaction. If we haven't downloaded them, we fail.
         val attachments = attachments.map {
-            services.storageService.attachments.openAttachment(it) ?: throw FileNotFoundException(it.toString())
+            services.storageService.attachments.openAttachment(it) ?: throw AttachmentResolutionException(it)
         }
         val resolvedInputs = inputs.map { StateAndRef(services.loadState(it), it) }
         return LedgerTransaction(resolvedInputs, outputs, authenticatedArgs, attachments, id, notary, mustSign, timestamp, type)
diff --git a/core/src/main/kotlin/net/corda/core/utilities/UntrustworthyData.kt b/core/src/main/kotlin/net/corda/core/utilities/UntrustworthyData.kt
index b220ea20ca..7db3d496df 100644
--- a/core/src/main/kotlin/net/corda/core/utilities/UntrustworthyData.kt
+++ b/core/src/main/kotlin/net/corda/core/utilities/UntrustworthyData.kt
@@ -18,11 +18,18 @@ class UntrustworthyData<out T>(private val fromUntrustedWorld: T) {
         @Deprecated("Accessing the untrustworthy data directly without validating it first is a bad idea")
         get() = fromUntrustedWorld
 
-    @Suppress("DEPRECATION")
     @Throws(FlowException::class)
-    inline fun <R> unwrap(validator: (T) -> R) = validator(data)
+    fun <R> unwrap(validator: Validator<T, R>) = validator.validate(fromUntrustedWorld)
 
     @Suppress("DEPRECATION")
     @Deprecated("This old name was confusing, use unwrap instead", replaceWith = ReplaceWith("unwrap"))
     inline fun <R> validate(validator: (T) -> R) = validator(data)
+
+    interface Validator<in T, out R> {
+        @Throws(FlowException::class)
+        fun validate(data: T): R
+    }
 }
+
+@Suppress("DEPRECATION")
+inline fun <T, R> UntrustworthyData<T>.unwrap(validator: (T) -> R): R = validator(data)
diff --git a/core/src/main/kotlin/net/corda/flows/AbstractStateReplacementFlow.kt b/core/src/main/kotlin/net/corda/flows/AbstractStateReplacementFlow.kt
index a05f15dd1f..8d5e520b44 100644
--- a/core/src/main/kotlin/net/corda/flows/AbstractStateReplacementFlow.kt
+++ b/core/src/main/kotlin/net/corda/flows/AbstractStateReplacementFlow.kt
@@ -15,6 +15,7 @@ import net.corda.core.transactions.SignedTransaction
 import net.corda.core.transactions.WireTransaction
 import net.corda.core.utilities.ProgressTracker
 import net.corda.core.utilities.UntrustworthyData
+import net.corda.core.utilities.unwrap
 import net.corda.flows.AbstractStateReplacementFlow.Acceptor
 import net.corda.flows.AbstractStateReplacementFlow.Instigator
 
diff --git a/core/src/main/kotlin/net/corda/flows/FetchDataFlow.kt b/core/src/main/kotlin/net/corda/flows/FetchDataFlow.kt
index 0be2b1a081..1661476aae 100644
--- a/core/src/main/kotlin/net/corda/flows/FetchDataFlow.kt
+++ b/core/src/main/kotlin/net/corda/flows/FetchDataFlow.kt
@@ -7,6 +7,7 @@ import net.corda.core.crypto.SecureHash
 import net.corda.core.flows.FlowException
 import net.corda.core.flows.FlowLogic
 import net.corda.core.utilities.UntrustworthyData
+import net.corda.core.utilities.unwrap
 import net.corda.flows.FetchDataFlow.DownloadedVsRequestedDataMismatch
 import net.corda.flows.FetchDataFlow.HashNotFound
 import java.util.*
diff --git a/core/src/main/kotlin/net/corda/flows/NotaryFlow.kt b/core/src/main/kotlin/net/corda/flows/NotaryFlow.kt
index f29281fc7c..66ee378e51 100644
--- a/core/src/main/kotlin/net/corda/flows/NotaryFlow.kt
+++ b/core/src/main/kotlin/net/corda/flows/NotaryFlow.kt
@@ -5,8 +5,8 @@ import net.corda.core.crypto.DigitalSignature
 import net.corda.core.crypto.Party
 import net.corda.core.crypto.SignedData
 import net.corda.core.crypto.signWithECDSA
-import net.corda.core.flows.FlowLogic
 import net.corda.core.flows.FlowException
+import net.corda.core.flows.FlowLogic
 import net.corda.core.node.services.TimestampChecker
 import net.corda.core.node.services.UniquenessException
 import net.corda.core.node.services.UniquenessProvider
@@ -14,6 +14,7 @@ import net.corda.core.serialization.serialize
 import net.corda.core.transactions.SignedTransaction
 import net.corda.core.transactions.WireTransaction
 import net.corda.core.utilities.ProgressTracker
+import net.corda.core.utilities.unwrap
 
 object NotaryFlow {
     /**
diff --git a/core/src/main/kotlin/net/corda/flows/TwoPartyDealFlow.kt b/core/src/main/kotlin/net/corda/flows/TwoPartyDealFlow.kt
index f8ae8c5905..6e3556d85d 100644
--- a/core/src/main/kotlin/net/corda/flows/TwoPartyDealFlow.kt
+++ b/core/src/main/kotlin/net/corda/flows/TwoPartyDealFlow.kt
@@ -16,6 +16,7 @@ import net.corda.core.transactions.WireTransaction
 import net.corda.core.utilities.ProgressTracker
 import net.corda.core.utilities.UntrustworthyData
 import net.corda.core.utilities.trace
+import net.corda.core.utilities.unwrap
 import java.security.KeyPair
 
 /**
diff --git a/docs/source/example-code/src/main/kotlin/net/corda/docs/FxTransactionBuildTutorial.kt b/docs/source/example-code/src/main/kotlin/net/corda/docs/FxTransactionBuildTutorial.kt
index 02f25559eb..cf07bc3faf 100644
--- a/docs/source/example-code/src/main/kotlin/net/corda/docs/FxTransactionBuildTutorial.kt
+++ b/docs/source/example-code/src/main/kotlin/net/corda/docs/FxTransactionBuildTutorial.kt
@@ -14,6 +14,7 @@ import net.corda.core.flows.FlowLogic
 import net.corda.core.node.PluginServiceHub
 import net.corda.core.node.ServiceHub
 import net.corda.core.transactions.SignedTransaction
+import net.corda.core.utilities.unwrap
 import net.corda.flows.FinalityFlow
 import net.corda.flows.ResolveTransactionsFlow
 import java.util.*
diff --git a/docs/source/example-code/src/main/kotlin/net/corda/docs/WorkflowTransactionBuildTutorial.kt b/docs/source/example-code/src/main/kotlin/net/corda/docs/WorkflowTransactionBuildTutorial.kt
index 0818835fa1..099dc63b72 100644
--- a/docs/source/example-code/src/main/kotlin/net/corda/docs/WorkflowTransactionBuildTutorial.kt
+++ b/docs/source/example-code/src/main/kotlin/net/corda/docs/WorkflowTransactionBuildTutorial.kt
@@ -8,6 +8,7 @@ import net.corda.core.node.PluginServiceHub
 import net.corda.core.node.ServiceHub
 import net.corda.core.node.services.linearHeadsOfType
 import net.corda.core.transactions.SignedTransaction
+import net.corda.core.utilities.unwrap
 import net.corda.flows.FinalityFlow
 import java.security.PublicKey
 import java.time.Duration
diff --git a/finance/src/main/kotlin/net/corda/flows/IssuerFlow.kt b/finance/src/main/kotlin/net/corda/flows/IssuerFlow.kt
index ff946f0fa4..921a6120eb 100644
--- a/finance/src/main/kotlin/net/corda/flows/IssuerFlow.kt
+++ b/finance/src/main/kotlin/net/corda/flows/IssuerFlow.kt
@@ -9,6 +9,7 @@ import net.corda.core.node.PluginServiceHub
 import net.corda.core.serialization.OpaqueBytes
 import net.corda.core.transactions.SignedTransaction
 import net.corda.core.utilities.ProgressTracker
+import net.corda.core.utilities.unwrap
 import java.util.*
 
 /**
diff --git a/finance/src/main/kotlin/net/corda/flows/TwoPartyTradeFlow.kt b/finance/src/main/kotlin/net/corda/flows/TwoPartyTradeFlow.kt
index aadd430fe3..c1cfade1cf 100644
--- a/finance/src/main/kotlin/net/corda/flows/TwoPartyTradeFlow.kt
+++ b/finance/src/main/kotlin/net/corda/flows/TwoPartyTradeFlow.kt
@@ -13,6 +13,7 @@ import net.corda.core.transactions.TransactionBuilder
 import net.corda.core.transactions.WireTransaction
 import net.corda.core.utilities.ProgressTracker
 import net.corda.core.utilities.trace
+import net.corda.core.utilities.unwrap
 import java.security.KeyPair
 import java.util.*
 
diff --git a/node/src/integration-test/kotlin/net/corda/services/messaging/MQSecurityTest.kt b/node/src/integration-test/kotlin/net/corda/services/messaging/MQSecurityTest.kt
index 1a1018db51..c0df706bcc 100644
--- a/node/src/integration-test/kotlin/net/corda/services/messaging/MQSecurityTest.kt
+++ b/node/src/integration-test/kotlin/net/corda/services/messaging/MQSecurityTest.kt
@@ -10,6 +10,7 @@ import net.corda.core.getOrThrow
 import net.corda.core.messaging.CordaRPCOps
 import net.corda.core.random63BitValue
 import net.corda.core.seconds
+import net.corda.core.utilities.unwrap
 import net.corda.node.internal.Node
 import net.corda.node.services.User
 import net.corda.node.services.config.SSLConfiguration
diff --git a/node/src/main/kotlin/net/corda/node/services/persistence/DataVendingService.kt b/node/src/main/kotlin/net/corda/node/services/persistence/DataVendingService.kt
index d43fad7564..2b4dddeb5d 100644
--- a/node/src/main/kotlin/net/corda/node/services/persistence/DataVendingService.kt
+++ b/node/src/main/kotlin/net/corda/node/services/persistence/DataVendingService.kt
@@ -10,6 +10,7 @@ import net.corda.core.node.PluginServiceHub
 import net.corda.core.node.recordTransactions
 import net.corda.core.serialization.SingletonSerializeAsToken
 import net.corda.core.transactions.SignedTransaction
+import net.corda.core.utilities.unwrap
 import net.corda.flows.*
 import java.util.function.Function
 import javax.annotation.concurrent.ThreadSafe
diff --git a/node/src/test/kotlin/net/corda/node/services/statemachine/StateMachineManagerTests.kt b/node/src/test/kotlin/net/corda/node/services/statemachine/StateMachineManagerTests.kt
index b0ed7a81da..ce06994a5d 100644
--- a/node/src/test/kotlin/net/corda/node/services/statemachine/StateMachineManagerTests.kt
+++ b/node/src/test/kotlin/net/corda/node/services/statemachine/StateMachineManagerTests.kt
@@ -21,6 +21,7 @@ import net.corda.core.random63BitValue
 import net.corda.core.rootCause
 import net.corda.core.serialization.OpaqueBytes
 import net.corda.core.serialization.deserialize
+import net.corda.core.utilities.unwrap
 import net.corda.core.transactions.SignedTransaction
 import net.corda.core.transactions.TransactionBuilder
 import net.corda.flows.CashCommand
diff --git a/samples/irs-demo/src/main/kotlin/net/corda/irs/api/NodeInterestRates.kt b/samples/irs-demo/src/main/kotlin/net/corda/irs/api/NodeInterestRates.kt
index b524dedf9b..aedf23af3f 100644
--- a/samples/irs-demo/src/main/kotlin/net/corda/irs/api/NodeInterestRates.kt
+++ b/samples/irs-demo/src/main/kotlin/net/corda/irs/api/NodeInterestRates.kt
@@ -14,6 +14,7 @@ import net.corda.core.node.services.ServiceType
 import net.corda.core.serialization.SingletonSerializeAsToken
 import net.corda.core.transactions.FilteredTransaction
 import net.corda.core.utilities.ProgressTracker
+import net.corda.core.utilities.unwrap
 import net.corda.irs.flows.FixingFlow
 import net.corda.irs.flows.RatesFixFlow
 import net.corda.node.services.api.AcceptsFileUpload
diff --git a/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/ExitServerFlow.kt b/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/ExitServerFlow.kt
index 044036d19c..7b88cd12e2 100644
--- a/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/ExitServerFlow.kt
+++ b/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/ExitServerFlow.kt
@@ -7,6 +7,7 @@ import net.corda.core.flows.FlowLogic
 import net.corda.core.node.CordaPluginRegistry
 import net.corda.core.node.NodeInfo
 import net.corda.core.node.PluginServiceHub
+import net.corda.core.utilities.unwrap
 import net.corda.testing.node.MockNetworkMapCache
 import java.util.concurrent.TimeUnit
 import java.util.function.Function
diff --git a/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/RatesFixFlow.kt b/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/RatesFixFlow.kt
index 2bf9be5e1e..917cc2b9f1 100644
--- a/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/RatesFixFlow.kt
+++ b/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/RatesFixFlow.kt
@@ -10,6 +10,7 @@ import net.corda.core.flows.FlowLogic
 import net.corda.core.transactions.FilteredTransaction
 import net.corda.core.transactions.TransactionBuilder
 import net.corda.core.utilities.ProgressTracker
+import net.corda.core.utilities.unwrap
 import net.corda.irs.flows.RatesFixFlow.FixOutOfRange
 import net.corda.irs.utilities.suggestInterestRateAnnouncementTimeWindow
 import java.math.BigDecimal
diff --git a/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/UpdateBusinessDayFlow.kt b/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/UpdateBusinessDayFlow.kt
index d6918d9020..7f0d725f87 100644
--- a/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/UpdateBusinessDayFlow.kt
+++ b/samples/irs-demo/src/main/kotlin/net/corda/irs/flows/UpdateBusinessDayFlow.kt
@@ -7,6 +7,7 @@ import net.corda.core.node.CordaPluginRegistry
 import net.corda.core.node.NodeInfo
 import net.corda.core.node.PluginServiceHub
 import net.corda.core.utilities.ProgressTracker
+import net.corda.core.utilities.unwrap
 import net.corda.node.utilities.TestClock
 import net.corda.testing.node.MockNetworkMapCache
 import java.time.LocalDate
diff --git a/samples/simm-valuation-demo/src/main/kotlin/net/corda/vega/flows/IRSTradeFlow.kt b/samples/simm-valuation-demo/src/main/kotlin/net/corda/vega/flows/IRSTradeFlow.kt
index c9e60d7296..822c104c23 100644
--- a/samples/simm-valuation-demo/src/main/kotlin/net/corda/vega/flows/IRSTradeFlow.kt
+++ b/samples/simm-valuation-demo/src/main/kotlin/net/corda/vega/flows/IRSTradeFlow.kt
@@ -5,6 +5,7 @@ import net.corda.core.crypto.Party
 import net.corda.core.flows.FlowLogic
 import net.corda.core.node.PluginServiceHub
 import net.corda.core.transactions.SignedTransaction
+import net.corda.core.utilities.unwrap
 import net.corda.flows.TwoPartyDealFlow
 import net.corda.vega.contracts.IRSState
 import net.corda.vega.contracts.OGTrade
diff --git a/samples/simm-valuation-demo/src/main/kotlin/net/corda/vega/flows/SimmFlow.kt b/samples/simm-valuation-demo/src/main/kotlin/net/corda/vega/flows/SimmFlow.kt
index 40ba74a159..6617862b7c 100644
--- a/samples/simm-valuation-demo/src/main/kotlin/net/corda/vega/flows/SimmFlow.kt
+++ b/samples/simm-valuation-demo/src/main/kotlin/net/corda/vega/flows/SimmFlow.kt
@@ -18,6 +18,7 @@ import net.corda.core.messaging.Ack
 import net.corda.core.node.PluginServiceHub
 import net.corda.core.node.services.dealsWith
 import net.corda.core.transactions.SignedTransaction
+import net.corda.core.utilities.unwrap
 import net.corda.flows.AbstractStateReplacementFlow.Proposal
 import net.corda.flows.StateReplacementException
 import net.corda.flows.TwoPartyDealFlow
diff --git a/samples/trader-demo/src/main/kotlin/net/corda/traderdemo/flow/BuyerFlow.kt b/samples/trader-demo/src/main/kotlin/net/corda/traderdemo/flow/BuyerFlow.kt
index 1226e178b9..35382d9ba1 100644
--- a/samples/trader-demo/src/main/kotlin/net/corda/traderdemo/flow/BuyerFlow.kt
+++ b/samples/trader-demo/src/main/kotlin/net/corda/traderdemo/flow/BuyerFlow.kt
@@ -12,6 +12,7 @@ import net.corda.core.serialization.SingletonSerializeAsToken
 import net.corda.core.transactions.SignedTransaction
 import net.corda.core.utilities.Emoji
 import net.corda.core.utilities.ProgressTracker
+import net.corda.core.utilities.unwrap
 import net.corda.flows.TwoPartyTradeFlow
 import net.corda.node.services.persistence.NodeAttachmentService
 import java.nio.file.Path