public function convert_table( $to_type, $start ) {

		// Set some defaults
		$has_insert     = false;
		$from_tablename = '';
		$field_list     = $from_tables = $tablefield_array = array();

		// Toggle Table Name based on $to_type (destination)
		switch ( $to_type ) {
			case 'user' :
				$tablename = $this->wpdb->users;
				break;

			case 'tags' :
				$tablename = '';
				break;

			case 'forum_subscriptions' :
				$tablename = $this->wpdb->postmeta;
				break;

			case 'topic_subscriptions' :
				$tablename = $this->wpdb->postmeta;
				break;

			case 'favorites' :
				$tablename = $this->wpdb->postmeta;
				break;

			default :
				$tablename = $this->wpdb->posts;
		}

		// Get the fields from the destination table
		if ( ! empty( $tablename ) ) {
			$tablefield_array = $this->get_fields( $tablename );
		}

		/** Step 1 ************************************************************/

		// Loop through the field maps, and look for to_type matches
		foreach ( $this->field_map as $item ) {

			// Yay a match, and we have a from table, too
			if ( ( $item['to_type'] === $to_type ) && ! empty( $item['from_tablename'] ) ) {

				// $from_tablename was set from a previous loop iteration
				if ( ! empty( $from_tablename ) ) {

					// Doing some joining
					if ( ! in_array( $item['from_tablename'], $from_tables, true ) && in_array( $item['join_tablename'], $from_tables, true ) ) {
						$from_tablename .= ' ' . $item['join_type'] . ' JOIN ' . $this->opdb->prefix . $item['from_tablename'] . ' AS ' . $item['from_tablename'] . ' ' . $item['join_expression'];
					}

				// $from_tablename needs to be set
				} else {
					$from_tablename = $item['from_tablename'] . ' AS ' . $item['from_tablename'];
				}

				// Specific FROM expression data used
				if ( ! empty( $item['from_expression'] ) ) {

					// No 'WHERE' in expression
					if ( stripos( $from_tablename, "WHERE" ) === false ) {
						$from_tablename .= ' ' . $item['from_expression'];

					// 'WHERE' in expression, so replace with 'AND'
					} else {
						$from_tablename .= ' ' . str_replace( "WHERE", "AND", $item['from_expression'] );
					}
				}

				// Add tablename and fieldname to arrays, formatted for querying
				$from_tables[] = $item['from_tablename'];
				$field_list[]  = 'convert(' . $item['from_tablename'] . '.' . $item['from_fieldname'] . ' USING "' . $this->charset . '") AS ' . $item['from_fieldname'];
			}
		}

		/** Step 2 ************************************************************/

		// We have a $from_tablename, so we want to get some data to convert
		if ( ! empty( $from_tablename ) ) {

			// Update rows
			$this->count_rows_by_table( "{$this->opdb->prefix}{$from_tablename}" );

			// Get some data from the old forums
			$field_list  = array_unique( $field_list );
			$fields      = implode( ',', $field_list );
			$forum_query = "SELECT {$fields} FROM {$this->opdb->prefix}{$from_tablename} LIMIT {$start}, {$this->max_rows}";

			// Set this query as the last one ran
			$this->update_query( $forum_query );

			// Get results as an array
			$forum_array = $this->opdb->get_results( $forum_query, ARRAY_A );

			// Query returned some results
			if ( ! empty( $forum_array ) ) {

				// Loop through results
				foreach ( (array) $forum_array as $forum ) {

					// Reset some defaults
					$insert_post = $insert_postmeta = $insert_data = array();

					// Loop through field map, again...
					foreach ( $this->field_map as $row ) {

						// Types match and to_fieldname is present. This means
						// we have some work to do here.
						if ( ( $row['to_type'] === $to_type ) && isset( $row['to_fieldname'] ) ) {

							// This row has a destination that matches one of the
							// columns in this table.
							if ( in_array( $row['to_fieldname'], $tablefield_array, true ) ) {

								// Allows us to set default fields.
								if ( isset( $row['default'] ) ) {
									$insert_post[ $row['to_fieldname'] ] = $row['default'];

								// Translates a field from the old forum.
								} elseif ( isset( $row['callback_method'] ) ) {
									if ( ( 'callback_userid' === $row['callback_method'] ) && ( false === $this->convert_users ) ) {
										$insert_post[ $row['to_fieldname'] ] = $forum[ $row['from_fieldname'] ];
									} else {
										$insert_post[ $row['to_fieldname'] ] = call_user_func_array( array( $this, $row['callback_method'] ), array( $forum[ $row['from_fieldname'] ], $forum ) );
									}

								// Maps the field from the old forum.
								} else {
									$insert_post[ $row['to_fieldname'] ] = $forum[ $row['from_fieldname'] ];
								}

							// Destination field is not empty, so we might need
							// to do some extra work or set a default.
							} elseif ( ! empty( $row['to_fieldname'] ) ) {

								// Allows us to set default fields.
								if ( isset( $row['default'] ) ) {
									$insert_postmeta[ $row['to_fieldname'] ] = $row['default'];

								// Translates a field from the old forum.
								} elseif ( isset( $row['callback_method'] ) ) {
									if ( ( $row['callback_method'] === 'callback_userid' ) && ( false === $this->convert_users ) ) {
										$insert_postmeta[ $row['to_fieldname'] ] = $forum[ $row['from_fieldname'] ];
									} else {
										$insert_postmeta[ $row['to_fieldname'] ] = call_user_func_array( array( $this, $row['callback_method'] ), array( $forum[ $row['from_fieldname'] ], $forum ) );
									}

								// Maps the field from the old forum.
								} else {
									$insert_postmeta[ $row['to_fieldname'] ] = $forum[ $row['from_fieldname'] ];
								}
							}
						}
					}

					/** Step 3 ************************************************/

					// Something to insert into the destination field
					if ( count( $insert_post ) > 0 || ( $to_type == 'tags' && count( $insert_postmeta ) > 0 ) ) {

						switch ( $to_type ) {

							/** New user **************************************/

							case 'user' :
								if ( username_exists( $insert_post['user_login'] ) ) {
									$insert_post['user_login'] = "imported_{$insert_post['user_login']}";
								}

								if ( email_exists( $insert_post['user_email'] ) ) {
									$insert_post['user_email'] = "imported_{$insert_post['user_email']}";
								}

								if ( empty( $insert_post['user_pass'] ) ) {
									$insert_post['user_pass'] = '';
								}

								// Internally re-calls _exists() checks above.
								// Also checks for existing nicename.
								$post_id = wp_insert_user( $insert_post );

								if ( is_numeric( $post_id ) ) {
									foreach ( $insert_postmeta as $key => $value ) {
										add_user_meta( $post_id, $key, $value, true );

										if ( '_id' == substr( $key, -3 ) && ( true === $this->sync_table ) ) {
											$this->wpdb->insert( $this->sync_table_name, array(
												'value_type' => 'user',
												'value_id'   => $post_id,
												'meta_key'   => $key,
												'meta_value' => $value
											) );
										}
									}
								}
								break;

							/** New Topic-Tag *********************************/

							case 'tags' :
								$post_id = wp_set_object_terms( $insert_postmeta['objectid'], $insert_postmeta['name'], 'topic-tag', true );
								$term = get_term_by( 'name', $insert_postmeta['name'], 'topic-tag');
								if ( false !== $term ) {
									wp_update_term( $term->term_id, 'topic-tag', array(
										'description' => $insert_postmeta['description'],
										'slug'        => $insert_postmeta['slug']
									) );
								}
								break;

							/** Forum Subscriptions ***************************/

							case 'forum_subscriptions' :
								$user_id = $insert_post['user_id'];
								$items   = wp_list_pluck( $insert_postmeta, '_bbp_forum_subscriptions' );
								if ( is_numeric( $user_id ) && ! empty( $items ) ) {
									foreach ( $items as $value ) {

										// Maybe string with commas
										$value = is_string( $value )
											? explode( ',', $value )
											: (array) $value;

										// Add user ID to forums subscribed users
										foreach ( $value as $fav ) {
											bbp_add_user_subscription( $user_id, $this->callback_forumid( $fav ) );
										}
									}
								}
								break;

							/** Subscriptions *********************************/

							case 'topic_subscriptions' :
								$user_id = $insert_post['user_id'];
								$items   = wp_list_pluck( $insert_postmeta, '_bbp_subscriptions' );
								if ( is_numeric( $user_id ) && ! empty( $items ) ) {
									foreach ( $items as $value ) {

										// Maybe string with commas
										$value = is_string( $value )
											? explode( ',', $value )
											: (array) $value;

										// Add user ID to topics subscribed users
										foreach ( $value as $fav ) {
											bbp_add_user_subscription( $user_id, $this->callback_topicid( $fav ) );
										}
									}
								}
								break;

							/** Favorites *************************************/

							case 'favorites' :
								$user_id = $insert_post['user_id'];
								$items   = wp_list_pluck( $insert_postmeta, '_bbp_favorites' );
								if ( is_numeric( $user_id ) && ! empty( $items ) ) {
									foreach ( $items as $value ) {

										// Maybe string with commas
										$value = is_string( $value )
											? explode( ',', $value )
											: (array) $value;

										// Add user ID to topics favorited users
										foreach ( $value as $fav ) {
											bbp_add_user_favorite( $user_id, $this->callback_topicid( $fav ) );
										}
									}
								}
								break;

							/** Forum, Topic, Reply ***************************/

							default :
								$post_id = wp_insert_post( $insert_post, true );

								if ( is_numeric( $post_id ) ) {
									foreach ( $insert_postmeta as $key => $value ) {
										add_post_meta( $post_id, $key, $value, true );

										/**
										 * If we are using the sync_table add
										 * the meta '_id' keys to the table
										 *
										 * Forums:  _bbp_old_forum_id         // The old forum ID
										 *          _bbp_old_forum_parent_id  // The old forum parent ID
										 *
										 * Topics:  _bbp_forum_id             // The new forum ID
										 *          _bbp_old_topic_id         // The old topic ID
										 *          _bbp_old_closed_status_id // The old topic open/closed status
										 *          _bbp_old_sticky_status_id // The old topic sticky status
										 *
										 * Replies: _bbp_forum_id             // The new forum ID
										 *          _bbp_topic_id             // The new topic ID
										 *          _bbp_old_reply_id         // The old reply ID
										 *          _bbp_old_reply_to_id      // The old reply to ID
										 */
										if ( '_id' === substr( $key, -3 ) && ( true === $this->sync_table ) ) {
											$this->wpdb->insert( $this->sync_table_name, array(
												'value_type' => 'post',
												'value_id'   => $post_id,
												'meta_key'   => $key,
												'meta_value' => $value
											) );
										}

										/**
										 * Replies need to save their old reply_to ID for
										 * hierarchical replies association. Later we update
										 * the _bbp_reply_to value with the new bbPress
										 * value using convert_reply_to_parents()
										 */
										if ( ( 'reply' === $to_type ) && ( '_bbp_old_reply_to_id' === $key ) ) {
											add_post_meta( $post_id, '_bbp_reply_to', $value );
										}
									}
								}
								break;
						}
						$has_insert = true;
					}
				}
			}
		}

		return ! $has_insert;
	}