diff --git a/capnp/helpers/capabilityHelper.cpp b/capnp/helpers/capabilityHelper.cpp
index 353f4b5..94f6591 100644
--- a/capnp/helpers/capabilityHelper.cpp
+++ b/capnp/helpers/capabilityHelper.cpp
@@ -122,11 +122,6 @@ kj::Promise<kj::Own<PyRefCounter>> wrapRemoteCall(kj::Own<PyRefCounter> func, ca
                           return wrapPyFunc(kj::mv(error_func), stealPyRef(wrap_kj_exception(arg))); } ));
 }
 
-::kj::Promise<kj::Own<PyRefCounter>> then(kj::Promise<kj::Array<kj::Own<PyRefCounter>> > && promise) {
-  return promise.then([](kj::Array<kj::Own<PyRefCounter>>&& arg) {
-    return stealPyRef(convert_array_pyobject(arg)); } );
-}
-
 kj::Promise<void> PythonInterfaceDynamicImpl::call(capnp::InterfaceSchema::Method method,
                          capnp::CallContext< capnp::DynamicStruct, capnp::DynamicStruct> context) {
     auto methodName = method.getProto().getName();
diff --git a/capnp/helpers/capabilityHelper.h b/capnp/helpers/capabilityHelper.h
index 7c81f50..8dee07c 100644
--- a/capnp/helpers/capabilityHelper.h
+++ b/capnp/helpers/capabilityHelper.h
@@ -84,8 +84,6 @@ inline kj::Promise<kj::Own<PyRefCounter>> wrapSizePromise(kj::Promise<size_t> pr
 ::kj::Promise<kj::Own<PyRefCounter>> then(kj::Own<kj::Promise<void>> promise,
                                           kj::Own<PyRefCounter>func, kj::Own<PyRefCounter> error_func);
 
-::kj::Promise<kj::Own<PyRefCounter>> then(kj::Promise<kj::Array<kj::Own<PyRefCounter>> > && promise);
-
 class PythonInterfaceDynamicImpl final: public capnp::DynamicCapability::Server {
 public:
   PyObject * py_server;
diff --git a/capnp/lib/capnp.pxd b/capnp/lib/capnp.pxd
index 9d95554..3350f14 100644
--- a/capnp/lib/capnp.pxd
+++ b/capnp/lib/capnp.pxd
@@ -160,7 +160,6 @@ cdef _setDynamicFieldStatic(DynamicStruct_Builder thisptr, field, value, parent)
 cdef api object wrap_dynamic_struct_reader(Response & r) with gil
 cdef api Promise[void] * call_server_method(
     object server, char * _method_name, CallContext & _context) except * with gil
-cdef api convert_array_pyobject(PyArray & arr) with gil
 cdef api object wrap_kj_exception(capnp.Exception & exception) with gil
 cdef api object wrap_kj_exception_for_reraise(capnp.Exception & exception) with gil
 cdef api object get_exception_info(object exc_type, object exc_obj, object exc_tb) with gil
diff --git a/capnp/lib/capnp.pyx b/capnp/lib/capnp.pyx
index 09a184f..5e74f94 100644
--- a/capnp/lib/capnp.pyx
+++ b/capnp/lib/capnp.pyx
@@ -154,12 +154,6 @@ cdef api VoidPromise * call_server_method(object server,
                 "Server function ({}) is not a coroutine"
                 .format(method_name, str(ret)))
 
-    return NULL
-
-
-cdef api object convert_array_pyobject(PyArray & arr) with gil:
-    return [<object>arr[i].get().obj for i in range(arr.size())]
-
 
 cdef api Own[Promise[Own[PyRefCounter]]] extract_promise(object obj):
     if type(obj) is _Promise:
@@ -2097,27 +2091,6 @@ cdef class _RemotePromise:
         self._parent = None # We don't need parent anymore. Setting to none allows quicker garbage collection
 
 
-cpdef join_promises(promises) except +reraise_kj_exception:
-    heap = capnp.heapArrayBuilderPyPromise(len(promises))
-
-    new_promises = []
-    new_promises_append = new_promises.append
-
-    for promise in promises:
-        promise_type = type(promise)
-        if promise_type is _Promise:
-            pyPromise = <_Promise>promise
-        elif promise_type is _RemotePromise or promise_type is _VoidPromise:
-            pyPromise = <_Promise>promise.as_pypromise()
-            new_promises_append(pyPromise)
-        else:
-            raise KjException(
-                "One of the promises passed to `join_promises` had a non promise value of: {}".format(promise))
-        heap.add(movePromise(deref(pyPromise.thisptr)))
-
-    return _Promise()._init(helpers.then(capnp.joinPromises(heap.finish())))
-
-
 cdef class _Request(_DynamicStructBuilder):
     cdef Request * thisptr_child
     cdef public bint is_consumed