PHPC-1377: Remove support for PHP 5.5

Author: alcaeus

.evergreen/config.yml

@@ -606,10 +606,6 @@ axes:
         display_name: "PHP 5.6"
         variables:
           PHP_VERSION: "5.6.38"
-      - id: "5.5"
-        display_name: "PHP 5.5"
-        variables:
-          PHP_VERSION: "5.5.38"
 
   - id: os-php5
     display_name: OS
@@ -667,7 +663,7 @@ axes:
 buildvariants:
 
 - matrix_name: "tests-php5"
-  matrix_spec: {"os-php5": "*", "versions": "4.0", "php-versions": ["5.5", "5.6"] }
+  matrix_spec: {"os-php5": "*", "versions": "4.0", "php-versions": "5.6" }
   display_name: "All: ${versions}/${php-versions} — ${os-php5}"
   tasks:
      - name: "test-standalone-ssl"

.travis.yml

@@ -21,10 +21,6 @@ matrix:
       env:
         - TESTS=tests/atlas.phpt
         - TEST_PHP_ARGS="-q -s output.txt -x --show-diff"
-    - php: 5.5
-      dist: trusty
-      env:
-        - SERVER_DISTRO=ubuntu1404
     - php: 5.6
     - php: 7.0
     - php: 7.1

CONTRIBUTING.md

@@ -192,14 +192,14 @@ executed directly.
 
 ### Ensure PHP version compatibility
 
-Ensure that the extension compiles on PHP 5.5 through the latest PHP 7.x
+Ensure that the extension compiles on PHP 5.6 through the latest PHP 7.x
 release. Be sure to test both ZTS and non-ZTS builds for PHP 5.x.
 
 ### Ensure Windows compatibility
 
 PECL will create Windows DLLs for new releases; however, you must ensure that
-the extension successfully builds on Windows before releasing. Note that PHP 5.5
-and 5.6 require VS2012, while PHP 7.x requires VS2015.
+the extension successfully builds on Windows before releasing. Note that PHP 5.6
+requires VS2012, while PHP 7.x requires VS2015.
 
 Given the following assumptions:
 

bin/package.xml.in

@@ -52,7 +52,7 @@ necessary to build a fully-functional MongoDB driver.
  <dependencies>
   <required>
    <php>
-    <min>5.5.0</min>
+    <min>5.6.0</min>
     <max>7.99.99</max>
    </php>
    <pearinstaller>

config.m4

@@ -20,8 +20,8 @@ if test "$PHP_MONGODB" != "no"; then
   fi
 
   AC_MSG_RESULT($PHP_MONGODB_PHP_VERSION)
-  if test "$PHP_MONGODB_PHP_VERSION_ID" -lt "50500"; then
-    AC_MSG_ERROR([not supported. Need a PHP version >= 5.5.0 (found $PHP_MONGODB_PHP_VERSION)])
+  if test "$PHP_MONGODB_PHP_VERSION_ID" -lt "50600"; then
+    AC_MSG_ERROR([not supported. Need a PHP version >= 5.6.0 (found $PHP_MONGODB_PHP_VERSION)])
   fi
 
   PHP_ARG_ENABLE([mongodb-developer-flags],