diff --git a/.circleci/config.yml b/.circleci/config.yml
index 7ec7b8a3..fd72071c 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -7,6 +7,7 @@ jobs:
     steps:
       - checkout
       - run: pip install -e .[all] .[test]
+      - run: pip install -q --no-deps git+https://github.com/davidhalter/jedi
       - run: py.test -v test/
       - run: pylint pyls test
       - run: pycodestyle pyls test
@@ -21,6 +22,7 @@ jobs:
       - run: python3 -m venv /tmp/pyenv
       - run: /tmp/pyenv/bin/python -m pip install loghub
       - run: pip install -e .[all] .[test]
+      - run: pip install -q --no-deps git+https://github.com/davidhalter/jedi
       - run: py.test -v test/
 
   lint:
diff --git a/appveyor.yml b/appveyor.yml
index 69e3e858..7ced096b 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -19,6 +19,7 @@ init:
 install:
   - "%PYTHON%/python.exe -m pip install --upgrade pip setuptools"
   - "%PYTHON%/python.exe -m pip install .[all] .[test]"
+  - "%PYTHON%/python.exe -m pip install -q --no-deps git+https://github.com/davidhalter/jedi"
 
 test_script:
   - "%PYTHON%/Scripts/pytest.exe -v test/"
diff --git a/pyls/plugins/jedi_completion.py b/pyls/plugins/jedi_completion.py
index caa543a1..9106c3c1 100644
--- a/pyls/plugins/jedi_completion.py
+++ b/pyls/plugins/jedi_completion.py
@@ -51,7 +51,11 @@
 @hookimpl
 def pyls_completions(config, document, position):
     try:
-        definitions = document.jedi_script(position).completions()
+        code_position = {}
+        if position:
+            code_position = {'line': position['line'] + 1,
+                             'column': _utils.clip_column(position['character'], document.lines, position['line'])}
+        definitions = document.jedi_script().complete(**code_position)
     except AttributeError as e:
         if 'CompiledObject' in str(e):
             # Needed to handle missing CompiledObject attribute
@@ -69,7 +73,7 @@ def pyls_completions(config, document, position):
     settings = config.plugin_settings('jedi_completion', document_path=document.path)
     should_include_params = settings.get('include_params')
     include_params = snippet_support and should_include_params and use_snippets(document, position)
-    return [_format_completion(d, include_params) for d in definitions] or None
+    return [_format_completion(signature, include_params) for d in definitions for signature in d.get_signatures()] or None
 
 
 def is_exception_class(name):
@@ -173,7 +177,7 @@ def _label(definition):
 def _detail(definition):
     try:
         return definition.parent().full_name or ''
-    except AttributeError:
+    except (AttributeError, TypeError):
         return definition.full_name or ''
 
 
diff --git a/pyls/workspace.py b/pyls/workspace.py
index a58b76a2..f5c72375 100644
--- a/pyls/workspace.py
+++ b/pyls/workspace.py
@@ -237,16 +237,11 @@ def jedi_script(self, position=None):
         environment = self.get_enviroment(environment_path) if environment_path else None
 
         kwargs = {
-            'source': self.source,
-            'path': self.path,
-            'sys_path': sys_path,
+            'code': self.source,
             'environment': environment,
+            'project': jedi.api.Project(self.path, sys_path=sys_path),
         }
 
-        if position:
-            kwargs['line'] = position['line'] + 1
-            kwargs['column'] = _utils.clip_column(position['character'], self.lines, position['line'])
-
         return jedi.Script(**kwargs)
 
     def get_enviroment(self, environment_path=None):
diff --git a/setup.py b/setup.py
index a56416a0..8120f91a 100755
--- a/setup.py
+++ b/setup.py
@@ -35,7 +35,7 @@
         'configparser; python_version<"3.0"',
         'future>=0.14.0; python_version<"3"',
         'backports.functools_lru_cache; python_version<"3.2"',
-        'jedi>=0.14.1,<0.16',
+        'jedi>=0.14.1',
         'python-jsonrpc-server>=0.3.2',
         'pluggy',
         'ujson<=1.35; platform_system!="Windows"'