Major features

Hybrid methods and properties added: https://docs.ponyorm.com/entities.html#hybrid-methods-and-properties
Allow to base queries on another queries: select(x.a for x in prev_query if x.b)
Added support of Python 3.7
Added support of PyPy
group_concat() aggregate function added
pony.flask subpackage added for integration with Flask

Other features

In SQLite3 LIKE is case sensitive now
#249: Fix incorrect mixin used for Timedelta
#251: correct dealing with qualified table names
#301: Fix aggregation over JSON Column
#306: Support of frozenset constants added
#308: Fixed an error when assigning JSON attribute value to the same attribute: obj.json_attr = obj.json_attr
#313: Fix missed retry on exception raised during db_session.__exit__
#314: Fix AttributeError: 'NoneType' object has no attribute 'seeds'
#315: Fix attribute lifting for JSON attributes
#321: Fix KeyError on obj.delete()
#325: duplicating percentage sign in raw SQL queries without parameters
#331: Overriding __len__ in entity fails
#336: entity declaration serialization
#357: reconnect after PostgreSQL server closed the connection unexpectedly
Fix Python implementation of between() function and rename arguments: between(a, x, y) ->
between(x, a, b)
Fix retry handling: in PostgreSQL and Oracle an error can be raised during commit
Fix optimistic update checks for composite foreign keys
Don't raise OptimisticCheckError if db_session is not optimistic
Handling incorrect datetime values in MySQL
Improved ImportError exception messages when MySQLdb, pymysql, psycopg2 or psycopg2cffi driver was not found
desc() function fixed to allow reverse its effect by calling desc(desc(x))
__contains__ method should check if objects belong to the same db_session
Fix pony.MODE detection; mod_wsgi detection according to official doc
A lot of inner fixes