• Support for new signer types: sha256Hash, preAuthTx.
• StrKey helper class with strkey encoding related methods.
• Removed deprecated methods: Keypair.isValidPublicKey (use StrKey), Keypair.isValidSecretKey (use StrKey), Keypair.fromSeed, Keypair.seed, Keypair.rawSeed.
• Breaking changes:
  • Network must be explicitly selected. Previously testnet was a default network.
  • Operation.setOptions() method signer param changed.
  • Keypair.fromAccountId() renamed to Keypair.fromPublicKey().
  • Keypair.accountId() renamed to Keypair.publicKey().
  • Dropping support for End-of-Life node versions.