Published on 2020-07-24.

* refactor(ios/engine): builds package download links (#3383)
* refactor(ios/engine): chained lexical model install callback, fix (#3388)
* feat(ios/engine): download queue concurrency (#3395)
* feat(ios/engine): keyboard search core (#3384)
* feat(ios/engine): support for deferred chaining of lexical model downloads (#3401)
* feat(ios/engine): use of Keyman staging sites (#3405)
* chore(ios/engine): dead code removal + deprecations (#3402)

Minor fixes and performance improvements