hi
in topicrow template you should have changeی $topic with $row
{{if $solvedComment = $row->getSolution() AND ( $solvedComment->hidden() == 0 OR ( \in_array( $solvedComment->hidden(), array( 1, -1 ) ) AND $solvedComment->canUnhide() ) )}}
{lang="solved_byline" htmlsprintf="$solvedComment->author()->name"}
{{endif}}
good luck!