[For 1.8] MyConversations: a conversation plugin for MyBB

[HLFadmin]

Upgrading to PHP 8.0, I see this warning when managing plugins.
MyConversations 1.2.4

The reference is in function cnv_get_unmigrated_pms_sql().
Line 1711
$last_pmid = max($last_pmid, $lrs_plugins[C_CNV]['max_draft_pmid']);

which is called in function cnv_get_unmigrated_pms_count()
Line 1725
$res = $db->query('SELECT COUNT(*) AS numrows FROM ('.cnv_get_unmigrated_pms_sql().') AS q');

Warning [2] Undefined array key "max_draft_pmid" - Line: 1711 - File: inc/plugins/converse/converse-functions.php PHP 8.0.27 (Linux)
File 	Line 	Function
/inc/class_error.php 	153 	errorHandler->error
/inc/plugins/converse/converse-functions.php 	1711 	errorHandler->error_callback
/inc/plugins/converse/converse-functions.php 	1725 	cnv_get_unmigrated_pms_sql
/inc/plugins/converse.php 	106 	cnv_get_unmigrated_pms_count
/admin/modules/config/plugins.php 	535 	converse_info
/admin/index.php 	830 	require

I've been putting off migrating to PHP 8, but should not delay much longer.

Mr. Laird, your help is always appreciated.