diff --git a/codex/codex.go b/codex/codex.go
index 24495b4..ab62c68 100644
--- a/codex/codex.go
+++ b/codex/codex.go
@@ -159,12 +159,12 @@ type Config struct {
 
 	// Default block timeout in seconds - 0 disables the ttl
 	// Default: 30 days
-	BlockTtl int `json:"block-ttl,omitempty"`
+	BlockTtl string `json:"block-ttl,omitempty"`
 
 	// Time interval in seconds - determines frequency of block
 	// maintenance cycle: how often blocks are checked for expiration and cleanup
 	// Default: 10 minutes
-	BlockMaintenanceInterval int `json:"block-mi,omitempty"`
+	BlockMaintenanceInterval string `json:"block-mi,omitempty"`
 
 	// Number of blocks to check every maintenance cycle
 	// Default: 1000
diff --git a/codex/codex_test.go b/codex/codex_test.go
index 15c6cc3..6d2bc9b 100644
--- a/codex/codex_test.go
+++ b/codex/codex_test.go
@@ -121,3 +121,33 @@ func TestCreateAndDestroyMultipleInstancesWithSameDatadir(t *testing.T) {
 		}
 	}
 }
+
+func TestNumThreads(t *testing.T) {
+	node := newCodexNode(t, Config{
+		NumThreads: 1,
+	})
+
+	if node == nil {
+		t.Fatal("expected codex node to be created")
+	}
+}
+
+func TestBlockTtl(t *testing.T) {
+	node := newCodexNode(t, Config{
+		BlockTtl: "10H",
+	})
+
+	if node == nil {
+		t.Fatal("expected codex node to be created")
+	}
+}
+
+func TestBlockMaintenanceInterval(t *testing.T) {
+	node := newCodexNode(t, Config{
+		BlockMaintenanceInterval: "10H",
+	})
+
+	if node == nil {
+		t.Fatal("expected codex node to be created")
+	}
+}
diff --git a/codex/testutil.go b/codex/testutil.go
index fb0471c..2d297da 100644
--- a/codex/testutil.go
+++ b/codex/testutil.go
@@ -47,6 +47,18 @@ func newCodexNode(t *testing.T, opts ...Config) *CodexNode {
 		if c.StorageQuota != 0 {
 			config.StorageQuota = c.StorageQuota
 		}
+
+		if c.NumThreads != 0 {
+			config.NumThreads = c.NumThreads
+		}
+
+		if c.BlockTtl != "" {
+			config.BlockTtl = c.BlockTtl
+		}
+
+		if c.BlockMaintenanceInterval != "" {
+			config.BlockMaintenanceInterval = c.BlockMaintenanceInterval
+		}
 	}
 
 	node, err := New(config)
diff --git a/vendor/nim-codex b/vendor/nim-codex
index c80d44f..2b9fc1e 160000
--- a/vendor/nim-codex
+++ b/vendor/nim-codex
@@ -1 +1 @@
-Subproject commit c80d44ff93057dd41e8ea3d55bef572eb503dfd2
+Subproject commit 2b9fc1eb554e5eee43b8a815084fb8c61687ada9