diff --git a/.travis.yml b/.travis.yml
index fb81f362f0..8ad9d2b3ac 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,12 +5,15 @@ sudo: false
 matrix:
     include:
         - php: 5.4
-          env: phpunit_exclude_groups=datetimeinterface
+          env: phpunit_exclude_groups=datetimeinterface dependencies=lowest
         - php: 5.5
         - php: 5.6
         - php: 7.0
         - php: 7.1
+        - php: 7.1
+          env: dependencies=lowest
         - php: 7.2
+          env: dependencies=lowest
 
 cache:
     directories:
@@ -24,15 +27,18 @@ before_install:
     - if [[ "$TRAVIS_PHP_VERSION" != 5.* ]]; then cp composer7.json composer.json; fi
 
 install:
-    - composer install --prefer-dist
+    - |
+        if [[ "$dependencies" = "lowest" ]]; then
+            composer update --prefer-lowest --prefer-stable -n
+        else
+            composer install --prefer-dist
+        fi
 
 script:
     - |
         if [[ ! $phpunit_exclude_groups ]]; then
-            echo "Debug: 'bin/phpunit -c tests/'"
             bin/phpunit -c tests/
         else
-            echo "Debug: 'bin/phpunit -c tests/ --exclude-group $phpunit_exclude_groups'"
             bin/phpunit -c tests/ --exclude-group $phpunit_exclude_groups
         fi
 
diff --git a/composer.json b/composer.json
index 34dd1e52cf..f8db0bd254 100644
--- a/composer.json
+++ b/composer.json
@@ -47,7 +47,10 @@
         "doctrine/orm": ">=2.5.0",
         "doctrine/common": ">=2.5.0",
         "symfony/yaml": "~2.6|~3.0|~4.0",
-        "phpunit/phpunit": "^4.8|^5.7|^6.5"
+        "phpunit/phpunit": "^4.8.35|^5.7|^6.5"
+    },
+    "conflict": {
+        "doctrine/annotations": "<1.2"
     },
     "suggest": {
         "doctrine/mongodb-odm": "to use the extensions with the MongoDB ODM",
diff --git a/composer7.json b/composer7.json
index fda3acbbcd..0b1f0a937e 100644
--- a/composer7.json
+++ b/composer7.json
@@ -42,7 +42,7 @@
         "behat/transliterator": "~1.2",
         "doctrine/common": "~2.4"
     },
-    "replace": {
+    "provide": {
         "ext-mongo": "1.6.12"
     },
     "require-dev": {
@@ -51,7 +51,12 @@
         "doctrine/orm": ">=2.5.0",
         "doctrine/common": ">=2.5.0",
         "symfony/yaml": "~2.6|~3.0|~4.0",
-        "phpunit/phpunit": "^4.8|^5.7|^6.5"
+        "phpunit/phpunit": "^5.7|^6.5"
+    },
+    "conflict": {
+        "doctrine/annotations": "<1.2",
+        "doctrine/mongodb": "<1.3",
+        "sebastian/comparator": "<2.0"
     },
     "suggest": {
         "doctrine/mongodb-odm": "to use the extensions with the MongoDB ODM",