I just tested version 1.2.1 on a fresh clean install of WordPress 4.3, and I am still getting notices:
<b>Notice</b>: The called constructor method for WP_Widget is <strong>deprecated</strong> since version 4.3.0! Use <pre>__construct()</pre> instead. in <b>/Users/bhubbard/Projects/agentone.dev/wp-includes/functions.php</b> on line <b>3457</b><br />
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<b>Notice</b>: The called constructor method for WP_Widget is <strong>deprecated</strong> since version 4.3.0! Use <pre>__construct()</pre> instead. in <b>/Users/bhubbard/Projects/agentone.dev/wp-includes/functions.php</b> on line <b>3457</b><br />
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<b>Warning</b>: Cannot modify header information - headers already sent by (output started at /Users/bhubbard/Projects/agentone.dev/wp-includes/functions.php:3457) in <b>/Users/bhubbard/Projects/agentone.dev/wp-includes/option.php</b> on line <b>787</b><br />
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<b>Warning</b>: Cannot modify header information - headers already sent by (output started at /Users/bhubbard/Projects/agentone.dev/wp-includes/functions.php:3457) in <b>/Users/bhubbard/Projects/agentone.dev/wp-includes/option.php</b> on line <b>788</b><br />