3.6.0

Implemented enhancements:

• do not hide Exceptions from custom handlers but correctly handle null #1169 (Hikariii)
• Handle ObjectConstructor returning NULL #1172 (jankramer)

Fixed bugs:

• Handle discriminator groups #1175 (goetas)

Merged pull requests:

• test serializing entity that uses Discriminator and extends some base… #1174 (FrKevin)
• test symfony translator contract #1171 (goetas)