diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index b6eb75b0f..98c300f49 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -10,10 +10,11 @@ jobs:
    steps:
    - name: install scala
      run: |
-       echo "deb https://dl.bintray.com/sbt/debian /" | sudo tee -a /etc/apt/sources.list.d/sbt.list
-       sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 2EE0EA64E40A89B84B2DF73499E82A75642AC823
+       echo "deb https://repo.scala-sbt.org/scalasbt/debian all main" | sudo tee /etc/apt/sources.list.d/sbt.list
+       echo "deb https://repo.scala-sbt.org/scalasbt/debian /" | sudo tee /etc/apt/sources.list.d/sbt_old.list
+       curl -sL "https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x2EE0EA64E40A89B84B2DF73499E82A75642AC823" | sudo apt-key add
        sudo apt-get update
-       sudo apt-get install -y sbt
+       sudo apt-get install sbt
        
    - uses: actions/checkout@v2
 
diff --git a/src/main/scala/vsys/blockchain/state/diffs/CommonValidation.scala b/src/main/scala/vsys/blockchain/state/diffs/CommonValidation.scala
index ff39f6838..789aeda3f 100644
--- a/src/main/scala/vsys/blockchain/state/diffs/CommonValidation.scala
+++ b/src/main/scala/vsys/blockchain/state/diffs/CommonValidation.scala
@@ -46,7 +46,9 @@ object CommonValidation {
        (c != ContractPermitted.contract &&
         c != ContractPermitted.contractWithoutSplit))
       Left(GenericError(s"deposit withdraw contracts must not appear before height=${settings.allowDepositWithdrawContractAfterHeight}"))
-    else Right(tx)
+    else if (c == ContractLock.contract || c == ContractPaymentChannel.contract || c == ContractNonFungible.contract || c == ContractPermitted.contract || c == ContractPermitted.contractWithoutSplit)
+      Right(tx)
+    else Left(GenericError(s"unsupported contracts"))
   }
 
   def disallowBeforeActivationHeight[T <: Transaction](settings: FunctionalitySettings, h: Int, tx: T): Either[ValidationError, T] =