diff --git a/.travis.yml b/.travis.yml
index 69880d1..dc035c8 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,187 +9,185 @@
     "submodules": false
   },
   "install": [
-    ". scripts/travis-install.sh",
-    "make -e install-dev",
-    "make -e install-$BUILD"
+    "if [ \"$BUILD_PRS\" = \"true\" ] || [ \"$TRAVIS_PULL_REQUEST\" = \"false\" ]; then\n    . scripts/travis-install.sh;\n    pip install -U pip;\n    pip install wheel;\n    make -e install-dev;\n    make -e install-$BUILD;\nfi"
   ],
   "language": "python",
   "matrix": {
     "include": [
       {
-        "env": "BUILD=style",
+        "env": "BUILD=style BUILD_PRS=true",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=devel",
+        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=devel BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=release",
+        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=release BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=minimal",
+        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=devel",
+        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=devel BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=release",
+        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=release BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=minimal",
+        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=devel",
+        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=devel BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=release",
+        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=release BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=minimal",
+        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=devel",
+        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=devel BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=release",
+        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=release BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=minimal",
+        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=devel",
+        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=devel BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=release",
+        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=release BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=minimal",
+        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "2.7"
       },
       {
-        "env": "BUILD=style",
+        "env": "BUILD=style BUILD_PRS=true",
         "python": "3.3"
       },
       {
-        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=devel",
+        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=devel BUILD_PRS=false",
         "python": "3.3"
       },
       {
-        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=release",
+        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=release BUILD_PRS=false",
         "python": "3.3"
       },
       {
-        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=minimal",
+        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "3.3"
       },
       {
-        "env": "BUILD=style",
+        "env": "BUILD=style BUILD_PRS=true",
         "python": "3.4"
       },
       {
-        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=devel",
+        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=devel BUILD_PRS=false",
         "python": "3.4"
       },
       {
-        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=release",
+        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=release BUILD_PRS=false",
         "python": "3.4"
       },
       {
-        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=minimal",
+        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "3.4"
       },
       {
-        "env": "BUILD=style",
+        "env": "BUILD=style BUILD_PRS=true",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=devel",
+        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=devel BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=release",
+        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=release BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=minimal",
+        "env": "BUILD=test REMOTESTORAGE_SERVER=mysteryshack REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=devel",
+        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=devel BUILD_PRS=true",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=release",
+        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=release BUILD_PRS=true",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=minimal",
+        "env": "BUILD=test DAV_SERVER=radicale REQUIREMENTS=minimal BUILD_PRS=true",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=devel",
+        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=devel BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=release",
+        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=release BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=minimal",
+        "env": "BUILD=test DAV_SERVER=owncloud REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=devel",
+        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=devel BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=release",
+        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=release BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=minimal",
+        "env": "BUILD=test DAV_SERVER=nextcloud REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=devel",
+        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=devel BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=release",
+        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=release BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=minimal",
+        "env": "BUILD=test DAV_SERVER=baikal REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=devel",
+        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=devel BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=release",
+        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=release BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=minimal",
+        "env": "BUILD=test DAV_SERVER=davical REQUIREMENTS=minimal BUILD_PRS=false",
         "python": "3.5"
       },
       {
-        "env": "BUILD=style",
+        "env": "BUILD=style BUILD_PRS=true",
         "python": "pypy"
       },
       {
@@ -199,6 +197,8 @@
       }
     ]
   },
-  "script": "make -e $BUILD",
+  "script": [
+    "if [ \"$BUILD_PRS\" = \"true\" ] || [ \"$TRAVIS_PULL_REQUEST\" = \"false\" ]; then\n    make -e $BUILD\nfi"
+  ],
   "sudo": true
 }
\ No newline at end of file
diff --git a/scripts/make_travisconf.py b/scripts/make_travisconf.py
index 6647e5f..e088896 100644
--- a/scripts/make_travisconf.py
+++ b/scripts/make_travisconf.py
@@ -3,6 +3,13 @@ import json
 import sys
 
 
+def script(x):
+    return """
+if [ "$BUILD_PRS" = "true" ] || [ "$TRAVIS_PULL_REQUEST" = "false" ]; then
+    {}
+fi
+    """.strip().format(x.strip())
+
 cfg = {}
 
 cfg['sudo'] = True
@@ -16,13 +23,17 @@ cfg['branches'] = {
     'only': ['auto', 'master']
 }
 
-cfg['install'] = [
-    ". scripts/travis-install.sh",
-    "make -e install-dev",
-    "make -e install-$BUILD"
-]
+cfg['install'] = [script("""
+    . scripts/travis-install.sh;
+    pip install -U pip;
+    pip install wheel;
+    make -e install-dev;
+    make -e install-$BUILD;
+""")]
 
-cfg['script'] = "make -e $BUILD"
+cfg['script'] = [script("""
+    make -e $BUILD
+""")]
 
 matrix = []
 cfg['matrix'] = {'include': matrix}
@@ -30,7 +41,7 @@ cfg['matrix'] = {'include': matrix}
 for python in ("2.7", "3.3", "3.4", "3.5", "pypy"):
     matrix.append({
         'python': python,
-        'env': 'BUILD=style'
+        'env': 'BUILD=style BUILD_PRS=true'
     })
 
     if python == "3.5":
@@ -54,14 +65,22 @@ for python in ("2.7", "3.3", "3.4", "3.5", "pypy"):
         ),
         ("devel", "release", "minimal")
     ):
+        build_prs = (
+            python == "3.5" and
+            server_type == 'DAV' and
+            server == 'radicale'
+        )
+
         matrix.append({
             'python': python,
             'env': ("BUILD=test "
                     "{server_type}_SERVER={server} "
-                    "REQUIREMENTS={requirements}"
+                    "REQUIREMENTS={requirements} "
+                    "BUILD_PRS={build_prs}"
                     .format(server_type=server_type,
                             server=server,
-                            requirements=requirements))
+                            requirements=requirements,
+                            build_prs='true' if build_prs else 'false'))
         })
 
 matrix.append({
diff --git a/scripts/travis-install.sh b/scripts/travis-install.sh
index 1e08cef..2dc277e 100644
--- a/scripts/travis-install.sh
+++ b/scripts/travis-install.sh
@@ -24,6 +24,3 @@ if [ "$TRAVIS_OS_NAME" = "osx" ]; then
     virtualenv -p python3 $HOME/osx-py3
     . $HOME/osx-py3/bin/activate
 fi
-
-pip install -U pip
-pip install wheel