diff --git a/Dockerfile b/Dockerfile
index ea99ab1..89e531a 120000
--- a/Dockerfile
+++ b/Dockerfile
@@ -1 +1 @@
-Dockerfile-3.4
\ No newline at end of file
+Dockerfile-3.5
\ No newline at end of file
diff --git a/Dockerfile-2.7 b/Dockerfile-2.7
index c4953ad..8589bcf 100644
--- a/Dockerfile-2.7
+++ b/Dockerfile-2.7
@@ -1,5 +1,9 @@
-from python:2.7-onbuild
+from python:2.7-slim
 
+WORKDIR /usr/src/app
+ADD requirements.txt /usr/src/app/
+RUN pip install -r requirements.txt
+ADD . /usr/src/app/
 RUN pip install .
 
 ENTRYPOINT ["python", "-m", "senpy", "-f", ".", "--host", "0.0.0.0"]
diff --git a/Dockerfile-3.4 b/Dockerfile-3.4
index a6e979e..15867bc 100644
--- a/Dockerfile-3.4
+++ b/Dockerfile-3.4
@@ -1,5 +1,9 @@
-from python:3.4-onbuild
+from python:3.4-slim
 
+WORKDIR /usr/src/app
+ADD requirements.txt /usr/src/app/
+RUN pip install -r requirements.txt
+ADD . /usr/src/app/
 RUN pip install .
 
 ENTRYPOINT ["python", "-m", "senpy", "-f", ".", "--host", "0.0.0.0"]
diff --git a/Dockerfile-3.5 b/Dockerfile-3.5
new file mode 100644
index 0000000..52dd691
--- /dev/null
+++ b/Dockerfile-3.5
@@ -0,0 +1,9 @@
+from python:3.5-slim
+
+WORKDIR /usr/src/app
+ADD requirements.txt /usr/src/app/
+RUN pip install -r requirements.txt
+ADD . /usr/src/app/
+RUN pip install .
+
+ENTRYPOINT ["python", "-m", "senpy", "-f", ".", "--host", "0.0.0.0"]
diff --git a/Dockerfile.template b/Dockerfile.template
index a75a9cb..cc04038 100644
--- a/Dockerfile.template
+++ b/Dockerfile.template
@@ -1,5 +1,9 @@
-from python:{{PYVERSION}}-onbuild
+from python:{{PYVERSION}}-slim
 
+WORKDIR /usr/src/app
+ADD requirements.txt /usr/src/app/
+RUN pip install -r requirements.txt
+ADD . /usr/src/app/
 RUN pip install .
 
 ENTRYPOINT ["python", "-m", "senpy", "-f", ".", "--host", "0.0.0.0"]
diff --git a/MANIFEST.in b/MANIFEST.in
index e6cb3ac..10d2ca8 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -7,4 +7,4 @@ graft senpy/plugins
 graft senpy/schemas
 graft senpy/templates
 graft senpy/static
-graft img
+graft img
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 8bdf433..45a06e5 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-PYVERSIONS=3.4 2.7
+PYVERSIONS=3.5 3.4 2.7
 PYMAIN=$(firstword $(PYVERSIONS))
 NAME=senpy
 REPO=gsiupm
@@ -16,6 +16,7 @@ dev:
 	pre-commit install
 
 dockerfiles: $(addprefix Dockerfile-,$(PYVERSIONS))
+	@unlink Dockerfile >/dev/null
 	ln -s Dockerfile-$(PYMAIN) Dockerfile
 
 Dockerfile-%: Dockerfile.template
@@ -35,7 +36,7 @@ test: $(addprefix test-,$(PYMAIN))
 
 testall: $(addprefix test-,$(PYVERSIONS))
 
-debug-%: build-debug-%
+debug-%:
 	docker run --rm -w /usr/src/app/ -v $$PWD:/usr/src/app --entrypoint=/bin/bash -ti $(NAME)-debug ;
 
 debug: debug-$(PYMAIN)
diff --git a/senpy/VERSION b/senpy/VERSION
index 142f9ea..c4fdcc6 100644
--- a/senpy/VERSION
+++ b/senpy/VERSION
@@ -1 +1 @@
-0.7.0-dev2
+0.7.0-dev3
diff --git a/senpy/extensions.py b/senpy/extensions.py
index fe36249..1583d96 100644
--- a/senpy/extensions.py
+++ b/senpy/extensions.py
@@ -2,9 +2,6 @@
 """
 from future import standard_library
 standard_library.install_aliases()
-import gevent
-from gevent import monkey
-monkey.patch_all()
 
 from .plugins import SentimentPlugin
 from .models import Error
@@ -12,7 +9,8 @@ from .blueprints import api_blueprint, demo_blueprint
 from .api import API_PARAMS, NIF_PARAMS, parse_params
 
 from git import Repo, InvalidGitRepositoryError
-from functools import partial
+
+from threading import Thread
 
 import os
 import fnmatch
@@ -154,20 +152,23 @@ class Senpy(object):
         logger.info("Activating plugin: {}".format(plugin.name))
 
         def act():
+            success = False
             try:
                 plugin.activate()
-                logger.info("Plugin activated: {}".format(plugin.name))
+                msg = "Plugin activated: {}".format(plugin.name)
+                logger.info(msg)
+                success = True
+                self._set_active_plugin(plugin_name, success)
             except Exception as ex:
-                logger.error("Error activating plugin {}: {}".format(
-                    plugin.name, ex))
-                logger.error("Trace: {}".format(traceback.format_exc()))
-
-        th = gevent.spawn(act)
-        th.link_value(partial(self._set_active_plugin, plugin_name, True))
+                msg = "Error activating plugin {} - {} : \n\t{}".format(
+                    plugin.name, ex, ex.format_exc())
+                logger.error(msg)
+                raise Error(msg)
         if sync:
-            th.join()
+            act()
         else:
-            return th
+            th = Thread(target=act)
+            th.start()
 
     def deactivate_plugin(self, plugin_name, sync=False):
         try:
@@ -176,6 +177,8 @@ class Senpy(object):
             raise Error(
                 message="Plugin not found: {}".format(plugin_name), status=404)
 
+        self._set_active_plugin(plugin_name, False)
+
         def deact():
             try:
                 plugin.deactivate()
@@ -185,12 +188,11 @@ class Senpy(object):
                     plugin.name, ex))
                 logger.error("Trace: {}".format(traceback.format_exc()))
 
-        th = gevent.spawn(deact)
-        th.link_value(partial(self._set_active_plugin, plugin_name, False))
         if sync:
-            th.join()
+            deact()
         else:
-            return th
+            th = Thread(target=deact)
+            th.start()
 
     def reload_plugin(self, name):
         logger.debug("Reloading {}".format(name))
diff --git a/setup.py b/setup.py
index a47fa6d..f33fe4f 100644
--- a/setup.py
+++ b/setup.py
@@ -23,10 +23,9 @@ setup(
     name='senpy',
     packages=['senpy'],  # this must be the same as the name above
     version=__version__,
-    description='''
-    A sentiment analysis server implementation. Designed to be \
-extendable, so new algorithms and sources can be used.
-    ''',
+    description=('A sentiment analysis server implementation. '
+                 'Designed to be extensible, so new algorithms '
+                 'and sources can be used.'),
     author='J. Fernando Sanchez',
     author_email='balkian@gmail.com',
     url='https://github.com/gsi-upm/senpy',  # use the URL to the github repo