diff --git a/nitro.nimble b/nitro.nimble
index 59c079d..d4f5284 100644
--- a/nitro.nimble
+++ b/nitro.nimble
@@ -1,11 +1,11 @@
-version = "0.1.0"
+version = "0.2.0"
 author = "Nim Nitro developers"
 license = "MIT"
 description = "Nitro state channels"
 
 requires "nim >= 1.2.6 & < 2.0.0"
 requires "nimcrypto >= 0.5.4 & < 0.6.0"
-requires "questionable >= 0.4.3 & < 0.5.0"
+requires "questionable >= 0.5.0 & < 0.6.0"
 requires "upraises >= 0.1.0 & < 0.2.0"
 requires "secp256k1"
 requires "stint"
diff --git a/nitro/protocol/signature.nim b/nitro/protocol/signature.nim
index a3e0e63..843502a 100644
--- a/nitro/protocol/signature.nim
+++ b/nitro/protocol/signature.nim
@@ -32,7 +32,7 @@ func recover(signature: Signature, hash: array[32, byte]): ?EthPublicKey =
 
 func recover*(signature: Signature, state: State): ?EthAddress =
   let hash = hashMessage(hashState(state))
-  recover(signature, hash)?.toAddress
+  recover(signature, hash).?toAddress
 
 func verify*(signature: Signature, state: State, signer: EthAddress): bool =
   recover(signature, state) == signer.some
diff --git a/nitro/wallet/wallet.nim b/nitro/wallet/wallet.nim
index 0879e3b..f5a9f68 100644
--- a/nitro/wallet/wallet.nim
+++ b/nitro/wallet/wallet.nim
@@ -70,13 +70,13 @@ func acceptChannel*(wallet: var Wallet, signed: SignedState): ?!ChannelId =
   wallet.createChannel(signed)
 
 func latestSignedState*(wallet: Wallet, channel: ChannelId): ?SignedState =
-  wallet.channels?[channel]
+  wallet.channels.?[channel]
 
 func state*(wallet: Wallet, channel: ChannelId): ?State =
-  wallet.latestSignedState(channel)?.state
+  wallet.latestSignedState(channel).?state
 
 func signatures*(wallet: Wallet, channel: ChannelId): ?seq[Signature] =
-  wallet.latestSignedState(channel)?.signatures
+  wallet.latestSignedState(channel).?signatures
 
 func signature*(wallet: Wallet,
                 channel: ChannelId,
@@ -92,7 +92,7 @@ func balance(state: State,
              asset: EthAddress,
              destination: Destination): UInt256 =
   if balances =? state.outcome.balances(asset):
-    if balance =? (balances?[destination]):
+    if balance =? balances.?[destination]:
       balance
     else:
       0.u256
@@ -140,7 +140,7 @@ func pay*(wallet: var Wallet,
       ?balances.move(wallet.destination, receiver, amount)
       state.outcome.update(asset, balances)
       wallet.updateChannel(SignedState(state: state))
-      ok(wallet.channels?[channel].get)
+      ok(wallet.channels.?[channel].get)
     else:
       SignedState.failure "asset not found"
   else:
@@ -178,7 +178,7 @@ func acceptPayment*(wallet: var Wallet,
     return void.failure "missing signature on payment"
 
   if updatedBalances =? payment.state.outcome.balances(asset):
-    var expectedState: State = wallet.channels?[channel]?.state.get
+    var expectedState: State = wallet.channels.?[channel].?state.get
     expectedState.outcome.update(asset, updatedBalances)
     if payment.state != expectedState:
       return void.failure "payment has unexpected changes in state"
diff --git a/tests/nitro/testWallet.nim b/tests/nitro/testWallet.nim
index 917f759..9939516 100644
--- a/tests/nitro/testWallet.nim
+++ b/tests/nitro/testWallet.nim
@@ -114,8 +114,8 @@ suite "wallet: making payments":
     wallet = Wallet.init(key)
     channel = wallet.openLedgerChannel(hub, chainId, nonce, asset, 42.u256).get
     let updated = wallet.pay(channel, asset, hub, 1.u256).option
-    check updated?.state == wallet.state(channel)
-    check updated?.signatures == wallet.signatures(channel)
+    check updated.?state == wallet.state(channel)
+    check updated.?signatures == wallet.signatures(channel)
 
   test "payment fails when channel not found":
     wallet = Wallet.init(key)