Fatal error running codesniffer (offset syntax with curly braces no longer supported)

Problem/Motivation

PHP Fatal error: Array and string offset access syntax with curly braces is no longer supported in ~/.config/composer/vendor/squizlabs/php_codesniffer/CodeSniffer/CLI.php

According to codesniffer, this is using old versions: https://github.com/squizlabs/PHP_CodeSniffer/issues/3590

Steps to reproduce

Very possibly my main question is why when i run "composer global require drupal/coder" i end up with version 8.x-2.0 and possibly consequently some obsolete dependencies?

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes