+ <news class="beta" date="2019 June 2.">
+ Parametrized applicability condition
+ allows λδ-2B to generalize both λδ-1A and λδ-1B.
+ </news>
+ <news class="beta" date="2019 April 16.">
+ Extended (λδ-2A) and restricted (λδ-1A) validity is decidable
+ (anniversary milestone).
+ </news>