Update one variable from Blob Object in SQLite

I had a app with version 3.2.1 and release version 3.2.2 now. In version 3.2.1 , I had an object with 2 variable for example Name and Email. at First , I Converted The Object to Byte with this code:

public <T> byte[] ObjectToByte(T Object){
    try {

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(baos);
        oos.writeObject(Object);
        byte[] ObjectAsBytes = baos.toByteArray();
        ByteArrayInputStream bais = new ByteArrayInputStream(ObjectAsBytes);
        return ObjectAsBytes;
    } catch (IOException e) {
        e.printStackTrace();
    }

    return null;
}

After that I stored this Object to SQLite by Type Blob. In Version 3.2.2 , I insert a variable to my object. for example Name , Email and Phone. But when I want get object from SQLite with below code , traditional users doesn't have Phone in object ,so my app to crash.

public <T> T ByteToObject(byte[] bytes){
    try {
        ByteArrayInputStream baip = new ByteArrayInputStream(bytes);
        ObjectInputStream ois = new ObjectInputStream(baip);
        T dataobj = (T ) ois.readObject();
        return dataobj ;

    } catch (IOException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }
    return null;
}

and

final mDataBase db = new mDataBase(context);
    db.createDB();
    Cursor cursor = db.ReadFromDB("select * from "+db.forum_table_v2 + " where " + db.ColType + " = " + "'" + type + "'");
    cursor.moveToFirst();
    if(cursor.getCount()>0){
        while (!cursor.isAfterLast()){
            Forum_Item forum_item = new Forum_Item();

            forum_item = ByteToObject(cursor.getBlob(cursor.getColumnIndex(db.ColForumItem)));
            itemList.add(forum_item);
            cursor.moveToNext();
        }
    }
    cursor.close();
    db.close();

How can i update old users database and object in database. please attention to : 1 - This object is Serializable 2 - I should update object for one variable. Thank you for attention.