There are several issues that make ElixirLS fail on OTP26. Some of them are already addressed on https://github.com/elixir-lsp/elixir-ls/tree/otp26 but some will need to wait for fixes upstream

• dialyzer changed some internal APIs we depend on
• changes in stdio interception
• calling self now crashes io
• OTP26 has critical bugs in stdio, e.g. [OTP 26] Unexpected conversion when transferring data over stdout erlang/otp#7132 Erlang/OTP 26 stdin fails on file:read/file:read_line erlang/otp#7230
• stdio hangs on Windows Erlang/OTP 26 write to stdout hangs in latin1 encoding on Windows erlang/otp#7459