Feather versions 2.6.5 and below are no longer able to send transactions. Upgrade Feather to 2.6.6 or above to fix the issue.
Users trying to construct a transaction on 2.6.5 and below are presented with the following error message:
“Internal error: Unrealistic number of outputs in output distribution".
The bug was triggered when the number of RingCT outputs on the blockchain exceeded 100 million.

• Fixes startup issues on some Linux distributions.

This is an emergency release to fix “Internal Error: Unrealistic number of outputs in output distribution” that prevented any transactions from being constructed.
The number of outputs on the blockchain exceeds a safety limit present in version 2.6.5 and below that was meant to mitigate output distribution poisoning. This caused a sanity check to fail during transaction construction.
Update your wallet to version 2.6.6 or later to resolve this issue.

• added a transaction pool viewer (Tools -> Tx Pool Viewer)
• send: options to enable ‘manual fee-tier selection’ and ‘subtract fee from amount’ were added to the transactions tab in the settings.
• send: in automatic fee mode, an option to use the ‘High’ fee-tier is presented if there is a backlog of 3 or more blocks at the ‘Normal’ fee-tier
• send: removed unnecessary RPC calls, which slightly speeds up construction on slow networks
• trezor: disabled bridge transport, improved error messages
• trezor: selecting an address in the Receive tab no longer requires device communication
• windows: more mitigations against false-positive AV detections
• fixed a potential crash on exit