diff --git a/mod/book/db/upgrade.php b/mod/book/db/upgrade.php
index 3fb10859cf3..c4709f003cd 100644
--- a/mod/book/db/upgrade.php
+++ b/mod/book/db/upgrade.php
@@ -40,6 +40,152 @@ function xmldb_book_upgrade($oldversion) {
     // Moodle v2.3.0 release upgrade line
     // Put any upgrade step following this
 
+    // Note: The next steps (up to 2012061710 included, are a "replay" of old upgrade steps,
+    // because some sites updated to Moodle 2.3 didn't have the latest contrib mod_book
+    // installed, so some required changes were missing.
+    //
+    // All the steps are run conditionally so sites upgraded from latest contrib mod_book or
+    // new (2.3 and upwards) sites won't get affected.
+    //
+    // See MDL-35297 and commit msg for more information.
+
+    if ($oldversion < 2012061703) {
+        // Rename field summary on table book to intro
+        $table = new xmldb_table('book');
+        $field = new xmldb_field('summary', XMLDB_TYPE_TEXT, null, null, null, null, null, 'name');
+
+        // Launch rename field summary
+        if ($dbman->field_exists($table, $field)) {
+            $dbman->rename_field($table, $field, 'intro');
+        }
+
+        // book savepoint reached
+        upgrade_mod_savepoint(true, 2012061703, 'book');
+    }
+
+    if ($oldversion < 2012061704) {
+        // Define field introformat to be added to book
+        $table = new xmldb_table('book');
+        $field = new xmldb_field('introformat', XMLDB_TYPE_INTEGER, '4', null, XMLDB_NOTNULL, null, '0', 'intro');
+
+        // Launch add field introformat
+        if (!$dbman->field_exists($table, $field)) {
+            $dbman->add_field($table, $field);
+            // Conditionally migrate to html format in intro
+            // Si está activo el htmleditor!!!!!
+            if ($CFG->texteditors !== 'textarea') {
+                $rs = $DB->get_recordset('book', array('introformat'=>FORMAT_MOODLE), '', 'id,intro,introformat');
+                foreach ($rs as $b) {
+                    $b->intro       = text_to_html($b->intro, false, false, true);
+                    $b->introformat = FORMAT_HTML;
+                    $DB->update_record('book', $b);
+                    upgrade_set_timeout();
+                }
+                unset($b);
+                $rs->close();
+            }
+        }
+
+        // book savepoint reached
+        upgrade_mod_savepoint(true, 2012061704, 'book');
+    }
+
+    if ($oldversion < 2012061705) {
+        // Define field introformat to be added to book
+        $table = new xmldb_table('book_chapters');
+        $field = new xmldb_field('contentformat', XMLDB_TYPE_INTEGER, '4', null, XMLDB_NOTNULL, null, '0', 'content');
+
+        // Launch add field introformat
+        if (!$dbman->field_exists($table, $field)) {
+            $dbman->add_field($table, $field);
+
+            $DB->set_field('book_chapters', 'contentformat', FORMAT_HTML, array());
+        }
+
+        // book savepoint reached
+        upgrade_mod_savepoint(true, 2012061705, 'book');
+    }
+
+    if ($oldversion < 2012061706) {
+        require_once("$CFG->dirroot/mod/book/db/upgradelib.php");
+
+        $sqlfrom = "FROM {book} b
+                    JOIN {modules} m ON m.name = 'book'
+                    JOIN {course_modules} cm ON (cm.module = m.id AND cm.instance = b.id)";
+
+        $count = $DB->count_records_sql("SELECT COUNT('x') $sqlfrom");
+
+        if ($rs = $DB->get_recordset_sql("SELECT b.id, b.course, cm.id AS cmid $sqlfrom ORDER BY b.course, b.id")) {
+
+            $pbar = new progress_bar('migratebookfiles', 500, true);
+
+            $i = 0;
+            foreach ($rs as $book) {
+                $i++;
+                upgrade_set_timeout(360); // set up timeout, may also abort execution
+                $pbar->update($i, $count, "Migrating book files - $i/$count.");
+
+                $context = context_module::instance($book->cmid);
+
+                mod_book_migrate_moddata_dir_to_legacy($book, $context, '/');
+
+                // remove dirs if empty
+                @rmdir("$CFG->dataroot/$book->course/$CFG->moddata/book/$book->id/");
+                @rmdir("$CFG->dataroot/$book->course/$CFG->moddata/book/");
+                @rmdir("$CFG->dataroot/$book->course/$CFG->moddata/");
+                @rmdir("$CFG->dataroot/$book->course/");
+            }
+            $rs->close();
+        }
+
+        // book savepoint reached
+        upgrade_mod_savepoint(true, 2012061706, 'book');
+    }
+
+    if ($oldversion < 2012061707) {
+        // Define field disableprinting to be dropped from book
+        $table = new xmldb_table('book');
+        $field = new xmldb_field('disableprinting');
+
+        // Conditionally launch drop field disableprinting
+        if ($dbman->field_exists($table, $field)) {
+            $dbman->drop_field($table, $field);
+        }
+
+        // book savepoint reached
+        upgrade_mod_savepoint(true, 2012061707, 'book');
+    }
+
+    if ($oldversion < 2012061708) {
+        unset_config('book_tocwidth');
+
+        // book savepoint reached
+        upgrade_mod_savepoint(true, 2012061708, 'book');
+    }
+
+    if ($oldversion < 2012061709) {
+        require_once("$CFG->dirroot/mod/book/db/upgradelib.php");
+
+        mod_book_migrate_all_areas();
+
+        upgrade_mod_savepoint(true, 2012061709, 'book');
+    }
+
+    if ($oldversion < 2012061710) {
+
+        // Define field revision to be added to book
+        $table = new xmldb_table('book');
+        $field = new xmldb_field('revision', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, null, '0', 'customtitles');
+
+        // Conditionally launch add field revision
+        if (!$dbman->field_exists($table, $field)) {
+            $dbman->add_field($table, $field);
+        }
+
+        // book savepoint reached
+        upgrade_mod_savepoint(true, 2012061710, 'book');
+    }
+    // End of MDL-35297 "replayed" steps.
 
     return true;
 }
diff --git a/mod/book/db/upgradelib.php b/mod/book/db/upgradelib.php
new file mode 100644
index 00000000000..5411930443c
--- /dev/null
+++ b/mod/book/db/upgradelib.php
@@ -0,0 +1,168 @@
+<?php
+// This file is part of Book module for Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Book module upgrade related helper functions
+ *
+ * @package    mod_book
+ * @copyright  2010 Petr Skoda {@link http://skodak.org}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die;
+
+/**
+ * Migrate book files stored in moddata folders.
+ *
+ * Please note it was a big mistake to store the files there in the first place!
+ *
+ * @param stdClass $book
+ * @param stdClass $context
+ * @param string $path
+ * @return void
+ */
+function mod_book_migrate_moddata_dir_to_legacy($book, $context, $path) {
+    global $OUTPUT, $CFG;
+
+    $base = "$CFG->dataroot/$book->course/$CFG->moddata/book/$book->id";
+    $fulldir = $base.$path;
+
+    if (!is_dir($fulldir)) {
+        // does not exist
+        return;
+    }
+
+    $fs      = get_file_storage();
+    $items   = new DirectoryIterator($fulldir);
+
+    foreach ($items as $item) {
+        if ($item->isDot()) {
+            unset($item); // release file handle
+            continue;
+        }
+
+        if ($item->isLink()) {
+            // do not follow symlinks - they were never supported in moddata, sorry
+            unset($item); // release file handle
+            continue;
+        }
+
+        if ($item->isFile()) {
+            if (!$item->isReadable()) {
+                echo $OUTPUT->notification(" File not readable, skipping: ".$fulldir.$item->getFilename());
+                unset($item); // release file handle
+                continue;
+            }
+
+            $filepath = clean_param("/$CFG->moddata/book/$book->id".$path, PARAM_PATH);
+            $filename = clean_param($item->getFilename(), PARAM_FILE);
+
+            if ($filename === '') {
+                // unsupported chars, sorry
+                unset($item); // release file handle
+                continue;
+            }
+
+            if (textlib::strlen($filepath) > 255) {
+                echo $OUTPUT->notification(" File path longer than 255 chars, skipping: ".$fulldir.$item->getFilename());
+                unset($item); // release file handle
+                continue;
+            }
+
+            if (!$fs->file_exists($context->id, 'course', 'legacy', '0', $filepath, $filename)) {
+                $file_record = array('contextid'=>$context->id, 'component'=>'course', 'filearea'=>'legacy', 'itemid'=>0, 'filepath'=>$filepath, 'filename'=>$filename,
+                                     'timecreated'=>$item->getCTime(), 'timemodified'=>$item->getMTime());
+                $fs->create_file_from_pathname($file_record, $fulldir.$item->getFilename());
+            }
+            $oldpathname = $fulldir.$item->getFilename();
+            unset($item); // release file handle
+            @unlink($oldpathname);
+
+        } else {
+            // migrate recursively all subdirectories
+            $oldpathname = $base.$item->getFilename().'/';
+            $subpath     = $path.$item->getFilename().'/';
+            unset($item);  // release file handle
+            mod_book_migrate_moddata_dir_to_legacy($book, $context, $subpath);
+            @rmdir($oldpathname); // deletes dir if empty
+        }
+    }
+    unset($items); // release file handles
+}
+
+/**
+ * Migrate legacy files in intro and chapters
+ * @return void
+ */
+function mod_book_migrate_all_areas() {
+    global $DB;
+
+    $rsbooks = $DB->get_recordset('book');
+    foreach($rsbooks as $book) {
+        upgrade_set_timeout(360); // set up timeout, may also abort execution
+        $cm = get_coursemodule_from_instance('book', $book->id);
+        $context = context_module::instance($cm->id);
+        mod_book_migrate_area($book, 'intro', 'book', $book->course, $context, 'mod_book', 'intro', 0);
+
+        $rschapters = $DB->get_recordset('book_chapters', array('bookid'=>$book->id));
+        foreach ($rschapters as $chapter) {
+            mod_book_migrate_area($chapter, 'content', 'book_chapters', $book->course, $context, 'mod_book', 'chapter', $chapter->id);
+        }
+        $rschapters->close();
+    }
+    $rsbooks->close();
+}
+
+/**
+ * Migrate one area, this should be probably part of moodle core...
+ *
+ * @param stdClass $record object to migrate files (book, chapter)
+ * @param string $field field in the record we are going to migrate
+ * @param string $table DB table containing the information to migrate
+ * @param int $courseid id of the course the book module belongs to
+ * @param context_module $context context of the book module
+ * @param string $component component to be used for the migrated files
+ * @param string $filearea filearea to be used for the migrated files
+ * @param int $itemid id to be used for the migrated files
+ * @return void
+ */
+function mod_book_migrate_area($record, $field, $table, $courseid, $context, $component, $filearea, $itemid) {
+    global $CFG, $DB;
+
+    $fs = get_file_storage();
+
+    foreach(array(get_site()->id, $courseid) as $cid) {
+        $matches = null;
+        $ooldcontext = context_course::instance($cid);
+        if (preg_match_all("|$CFG->wwwroot/file.php(\?file=)?/$cid(/[^\s'\"&\?#]+)|", $record->$field, $matches)) {
+            $file_record = array('contextid'=>$context->id, 'component'=>$component, 'filearea'=>$filearea, 'itemid'=>$itemid);
+            foreach ($matches[2] as $i=>$filepath) {
+                if (!$file = $fs->get_file_by_hash(sha1("/$ooldcontext->id/course/legacy/0".$filepath))) {
+                    continue;
+                }
+                try {
+                    if (!$newfile = $fs->get_file_by_hash(sha1("/$context->id/$component/$filearea/$itemid".$filepath))) {
+                        $fs->create_file_from_storedfile($file_record, $file);
+                    }
+                    $record->$field = str_replace($matches[0][$i], '@@PLUGINFILE@@'.$filepath, $record->$field);
+                } catch (Exception $ex) {
+                    // ignore problems
+                }
+                $DB->set_field($table, $field, $record->$field, array('id'=>$record->id));
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mod/book/version.php b/mod/book/version.php
index e187cb33144..f37c00d4531 100644
--- a/mod/book/version.php
+++ b/mod/book/version.php
@@ -25,6 +25,6 @@
 defined('MOODLE_INTERNAL') || die;
 
 $module->component = 'mod_book'; // Full name of the plugin (used for diagnostics)
-$module->version   = 2012061702; // The current module version (Date: YYYYMMDDXX)
+$module->version   = 2012061710; // The current module version (Date: YYYYMMDDXX)
 $module->requires  = 2012061700; // Requires this Moodle version
 $module->cron      = 0;          // Period for cron to check this module (secs)