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=================================
Upgrading from PySpark 1.4 to 1.5
=================================

* Resolution of strings to columns in Python now supports using dots (.) to qualify the column or access nested values. For example ``df['table.column.nestedField']``. However, this means that if your column name contains any dots you must now escape them using backticks (e.g., ``table.`column.with.dots`.nested``).

* DataFrame.withColumn method in PySpark supports adding a new column or replacing existing columns of the same name.