diff --git a/Cargo.toml b/Cargo.toml
index 7bc38b7..e00beef 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,8 +11,9 @@ crate-type = ["cdylib"]
 
 [dependencies]
 chrono = "0.4"
-tantivy = { git = "https://github.com/tantivy-search/tantivy", branch = "master" }
+tantivy = "0.11"
 itertools = "0.8"
+futures = "0.3"
 
 [dependencies.pyo3]
 version = "0.8"
diff --git a/src/document.rs b/src/document.rs
index 58a58ea..601f3f0 100644
--- a/src/document.rs
+++ b/src/document.rs
@@ -25,6 +25,10 @@ fn value_to_py(py: Python, value: &Value) -> PyResult<PyObject> {
         Value::I64(num) => (*num).into_py(py),
         Value::F64(num) => (*num).into_py(py),
         Value::Bytes(b) => b.to_object(py),
+        Value::PreTokStr(pretoken) => {
+            // TODO implement me
+            unimplemented!();
+        }
         Value::Date(d) => PyDateTime::new(
             py,
             d.year(),
@@ -50,6 +54,10 @@ fn value_to_string(value: &Value) -> String {
         Value::Bytes(bytes) => format!("{:?}", bytes),
         Value::Date(d) => format!("{:?}", d),
         Value::Facet(facet) => facet.to_string(),
+        Value::PreTokStr(pretok) => {
+            // TODO implement me
+            unimplemented!();
+        }
     }
 }
 
diff --git a/src/index.rs b/src/index.rs
index fd80297..c20af98 100644
--- a/src/index.rs
+++ b/src/index.rs
@@ -79,9 +79,11 @@ impl IndexWriter {
 
     /// Detect and removes the files that are not used by the index anymore.
     fn garbage_collect_files(&mut self) -> PyResult<()> {
-        self.inner_index_writer
-            .garbage_collect_files()
-            .map_err(to_pyerr)
+        use futures::executor::block_on;
+        block_on(self.inner_index_writer
+            .garbage_collect_files())
+            .map_err(to_pyerr)?;
+        Ok(())
     }
 
     /// The opstamp of the last successful commit.
@@ -130,6 +132,12 @@ impl IndexWriter {
                     field_name
                 )))
             }
+            Value::PreTokStr(pretok) => {
+                return Err(exceptions::ValueError::py_err(format!(
+                    "Field `{}` is pretokenized. This is not authorized for delete.",
+                    field_name
+                )))
+            }
         };
         Ok(self.inner_index_writer.delete_term(term.clone()))
     }
@@ -332,11 +340,10 @@ impl Index {
                 }
             }
         } else {
-            for (field_id, field_entry) in
-                self.index.schema().fields().iter().enumerate()
+            for (field, field_entry) in self.index.schema().fields()
             {
                 if field_entry.is_indexed() {
-                    default_fields.push(Field(field_id as u32));
+                    default_fields.push(field);
                 }
             }
         }