diff --git a/types/block.go b/types/block.go
index 3a12462e..bd2a1f00 100644
--- a/types/block.go
+++ b/types/block.go
@@ -49,6 +49,12 @@ func (b *Block) AddEvidence(evidence []Evidence) {
 // ValidateBasic performs basic validation that doesn't involve state data.
 // It checks the internal consistency of the block.
 func (b *Block) ValidateBasic() error {
+	if b == nil {
+		return errors.New("Nil blocks are invalid")
+	}
+	b.mtx.Lock()
+	defer b.mtx.Unlock()
+
 	newTxs := int64(len(b.Data.Txs))
 	if b.NumTxs != newTxs {
 		return fmt.Errorf("Wrong Block.Header.NumTxs. Expected %v, got %v", newTxs, b.NumTxs)
diff --git a/version/version.go b/version/version.go
index a4509542..b0123eb1 100644
--- a/version/version.go
+++ b/version/version.go
@@ -1,13 +1,13 @@
 package version
 
 const Maj = "0"
-const Min = "16"
+const Min = "19"
 const Fix = "0"
 
 var (
 	// Version is the current version of Tendermint
 	// Must be a string because scripts like dist.sh read this file.
-	Version = "0.16.0"
+	Version = "0.19.0"
 
 	// GitCommit is the current HEAD set using ldflags.
 	GitCommit string