diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2e155ba..81b56af 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,8 +1,13 @@
 # Changelog
 
-### Unreleased
+### 0.3.0 ~ 0.4.0 - 2018/Oct/4
 
-* List pending changes here.
+* [BREAKING] Switch logic operators from & and | to && and ||
+* Add an annotation @filter-default-field
+
+### 0.2.0 - 2018/Oct/3
+
+* Factor out filter hooks for better usability.
 
 ### 0.1.0 - 2018/Jul/18
 
diff --git a/README.md b/README.md
index 3a32ea3..8e1366b 100644
--- a/README.md
+++ b/README.md
@@ -51,7 +51,7 @@ $ mycmd example p1 p2 --filter='color~=#^red.*#'
 The filter decides whether to include or exclude each **top-level element** based on the result of evaluating the provided expression on each element.
 
 - Nested data elements may be tested, e.g. via `attributes.color=red`
-- Simple boolean logic may be used, e.g. `color=red&shape=round`
+- Simple boolean logic may be used, e.g. `color=red&&shape=round`
 
 Parenthesis are not supported.
 
diff --git a/VERSION b/VERSION
index 746bd19..25a5afd 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.3.1-dev
+0.4.0-dev
diff --git a/src/Operators/LogicalAndOp.php b/src/Operators/LogicalAndOp.php
index 7bb5d19..1023886 100644
--- a/src/Operators/LogicalAndOp.php
+++ b/src/Operators/LogicalAndOp.php
@@ -34,6 +34,6 @@ public function test(Data $row)
      */
     public function __toString()
     {
-        return "{$this->lhs}&{$this->rhs}";
+        return "{$this->lhs}&&{$this->rhs}";
     }
 }
diff --git a/src/Operators/LogicalOrOp.php b/src/Operators/LogicalOrOp.php
index 63bd5e8..8c1d79c 100644
--- a/src/Operators/LogicalOrOp.php
+++ b/src/Operators/LogicalOrOp.php
@@ -34,6 +34,6 @@ public function test(Data $row)
      */
     public function __toString()
     {
-        return "{$this->lhs}|{$this->rhs}";
+        return "{$this->lhs}||{$this->rhs}";
     }
 }
diff --git a/tests/FactoryTest.php b/tests/FactoryTest.php
index 2010d41..f1dd42f 100644
--- a/tests/FactoryTest.php
+++ b/tests/FactoryTest.php
@@ -33,19 +33,19 @@ public function testFactoryParsingValues()
             ['a!*=b', '!a*=b',],
             ['a!~=#b#', '!a~=#b#',],
 
-            ['a=b&c=d',],
-            ['a*=b|c=d',],
-            ['a~=#b#&c~=d',],
-            ['!a=b|!c=d',],
-            ['!a*=b&c*=d',],
-            ['!a~=#b#&c=d',],
-            ['a!=b&c!=d', '!a=b&!c=d',],
-            ['a!*=b|c!*=d', '!a*=b|!c*=d',],
-            ['a!~=#b#&c!~=#d#', '!a~=#b#&!c~=#d#',],
-
-            ['a=b&c=d&e=f',],
-            ['a=b|c=d&e=f',],
-            ['a=b|c=d|e=f',],
+            ['a=b&&c=d',],
+            ['a*=b||c=d',],
+            ['a~=#b#&&c~=d',],
+            ['!a=b||!c=d',],
+            ['!a*=b&&c*=d',],
+            ['!a~=#b#&&c=d',],
+            ['a!=b&&c!=d', '!a=b&&!c=d',],
+            ['a!*=b||c!*=d', '!a*=b||!c*=d',],
+            ['a!~=#b#&&c!~=#d#', '!a~=#b#&&!c~=#d#',],
+
+            ['a=b&&c=d&&e=f',],
+            ['a=b||c=d&&e=f',],
+            ['a=b||c=d||e=f',],
 
         ];
     }
@@ -100,16 +100,16 @@ public function testFactoryEvaluationValues()
             ['a.b~=#c#', ['a' => ['b' => 'abcd']], true,],
             ['a.b~=#c#', ['b' => ['b' => 'c']], false,],
 
-            ['a=b&c=d', ['a' => 'b', 'c' => 'd'], true,],
-            ['a=b&c=d', ['a' => 'b', 'c' => 'xd'], false,],
-            ['a=b|c=d', ['a' => 'b', 'c' => 'xd'], true,],
+            ['a=b&&c=d', ['a' => 'b', 'c' => 'd'], true,],
+            ['a=b&&c=d', ['a' => 'b', 'c' => 'xd'], false,],
+            ['a=b||c=d', ['a' => 'b', 'c' => 'xd'], true,],
 
-            ['a*=b&c*=d', ['a' => 'b', 'c' => 'd'], true,],
-            ['a*=b&c*=d', ['a' => 'b', 'c' => 'xd'], true,],
-            ['a*=b&c*=d', ['a' => 'b', 'c' => 'xy'], false,],
-            ['a*=b|c*=d', ['a' => 'b', 'c' => 'xd'], true,],
-            ['a*=b|c*=d', ['a' => 'xb', 'c' => 'xd'], true,],
-            ['a*=b|c*=d', ['a' => 'xy', 'c' => 'xy'], false,],
+            ['a*=b&&c*=d', ['a' => 'b', 'c' => 'd'], true,],
+            ['a*=b&&c*=d', ['a' => 'b', 'c' => 'xd'], true,],
+            ['a*=b&&c*=d', ['a' => 'b', 'c' => 'xy'], false,],
+            ['a*=b||c*=d', ['a' => 'b', 'c' => 'xd'], true,],
+            ['a*=b||c*=d', ['a' => 'xb', 'c' => 'xd'], true,],
+            ['a*=b||c*=d', ['a' => 'xy', 'c' => 'xy'], false,],
 
             ['a!=b', ['a' => 'b'], false,],
             ['a!=b', ['a' => 'abc'], true,],
diff --git a/tests/FilterOutputDataTest.php b/tests/FilterOutputDataTest.php
index 11ed08a..5ad683e 100644
--- a/tests/FilterOutputDataTest.php
+++ b/tests/FilterOutputDataTest.php
@@ -32,8 +32,8 @@ public function testFilterDataValues()
 
         return [
             [$source, 'color=red', 'a', ],
-            [$source, 'color=blue|shape=triangular', 'b,c', ],
-            [$source, 'color=red&shape=square', '', ],
+            [$source, 'color=blue||shape=triangular', 'b,c', ],
+            [$source, 'color=red&&shape=square', '', ],
         ];
     }
 
diff --git a/tests/OpCommandsTest.php b/tests/OpCommandsTest.php
index 12fab1f..a0731c8 100644
--- a/tests/OpCommandsTest.php
+++ b/tests/OpCommandsTest.php
@@ -53,13 +53,13 @@ public function exampleTestCommandParameters()
             ],
 
             [
-                'a=b&c=d|x=y', self::STATUS_OK,
-                'parse', 'a=b&c=d|x=y',
+                'a=b&&c=d||x=y', self::STATUS_OK,
+                'parse', 'a=b&&c=d||x=y',
             ],
 
             [
                 'Could not parse expression a', self::STATUS_ERROR,
-                'parse', 'a&b',
+                'parse', 'a&&b',
             ],
 
             [