diff --git a/.travis.yml b/.travis.yml
index 0b96f17..236155b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,16 +10,14 @@ addons:
 
 matrix:
   include:
-    - php: 5.4
-      env: DB=PGSQL CORE_RELEASE=3.2
     - php: 5.5
-      env: DB=PGSQL CORE_RELEASE=3.3
+      env: DB=PGSQL CORE_RELEASE=3.7
     - php: 5.6
-      env: DB=PGSQL CORE_RELEASE=3.4
+      env: DB=PGSQL CORE_RELEASE=3.7
     - php: 5.6
-      env: DB=MYSQL CORE_RELEASE=3.5
+      env: DB=MYSQL CORE_RELEASE=3.7
     - php: 7.0
-      env: DB=MYSQL CORE_RELEASE=3.6
+      env: DB=MYSQL CORE_RELEASE=3.7
     - php: 7.1
       env: DB=MYSQL CORE_RELEASE=3
 
diff --git a/_config.php b/_config.php
deleted file mode 100644
index e69de29..0000000
diff --git a/code/extractors/FileTextExtractor.php b/code/extractors/FileTextExtractor.php
index cc7c176..ddd3c5e 100644
--- a/code/extractors/FileTextExtractor.php
+++ b/code/extractors/FileTextExtractor.php
@@ -5,7 +5,7 @@
  * @author mstephens
  *
  */
-abstract class FileTextExtractor extends Object
+abstract class FileTextExtractor extends SS_Object
 {
     /**
      * Set priority from 0-100.
@@ -34,7 +34,7 @@ abstract class FileTextExtractor extends Object
         if (self::$sorted_extractor_classes) {
             return self::$sorted_extractor_classes;
         }
-        
+
         // Generate the sorted list of extractors on demand.
         $classes = ClassInfo::subclassesFor("FileTextExtractor");
         array_shift($classes);
@@ -108,7 +108,7 @@ abstract class FileTextExtractor extends Object
     /**
      * Checks if the extractor is supported on the current environment,
      * for example if the correct binaries or libraries are available.
-     * 
+     *
      * @return boolean
      */
     abstract public function isAvailable();
@@ -125,7 +125,7 @@ abstract class FileTextExtractor extends Object
     /**
      * Determine if this extractor suports the given mime type.
      * Will only be called if supportsExtension returns false.
-     * 
+     *
      * @param string $mime
      * @return boolean
      */
@@ -133,7 +133,7 @@ abstract class FileTextExtractor extends Object
 
     /**
      * Given a file path, extract the contents as text.
-     * 
+     *
      * @param string $path
      * @return string
      */
diff --git a/composer.json b/composer.json
index f8a6ea8..5b3a1e5 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
 	"require": {
 		"php": ">=5.3.2",
 		"composer/installers": "*",
-		"silverstripe/framework": "^3.1",
+		"silverstripe/framework": "^3.7",
 		"guzzle/guzzle": "^3.9",
 		"symfony/event-dispatcher": "^2.6.0@stable",
 		"symfony/http-foundation": "^2.6.0"
diff --git a/tests/FileTextExtractableTest.php b/tests/FileTextExtractableTest.php
index 166b1ee..3cf6798 100644
--- a/tests/FileTextExtractableTest.php
+++ b/tests/FileTextExtractableTest.php
@@ -26,15 +26,16 @@ class FileTextExtractableTest extends SapphireTest
         // Create a copy of the file, as it may be clobbered by the test
         // ($file->extractFileAsText() calls $file->write)
         copy(BASE_PATH.'/textextraction/tests/fixtures/test1.html', BASE_PATH.'/textextraction/tests/fixtures/test1-copy.html');
-        
+
         // Use HTML, since the extractor is always available
+        /** @var File&FileTextExtractable $file */
         $file = new File(array(
             'Name' => 'test1-copy.html',
             'Filename' => 'textextraction/tests/fixtures/test1-copy.html'
         ));
         $file->write();
-    
-        $content = $file->extractFileAsText();
+
+        $content = (string) $file->extractFileAsText();
         $this->assertContains('Test Headline', $content);
         $this->assertContains('Test Text', $content);
         $this->assertEquals($content, $file->FileContentCache);