Hi  @Lars,
If you want to change that navigation text, you will need to do a bit of customization using a Child theme. Please follow following steps:
1. Create A Child Theme for Catch Flames Pro. Details for child theme is here
2. Then you need to add following codes in your Child Theme’s functions.php file:
/**
 * Display navigation to next/previous pages when applicable
 */
function catchflames_content_nav( $nav_id ) {
	global $wp_query;
	/**
	 * Check Jetpack Infinite Scroll
	 * if it's active then disable pagination
	 */
	if ( class_exists( 'Jetpack', false ) ) {
		$jetpack_active_modules = get_option('jetpack_active_modules');
		if ( $jetpack_active_modules && in_array( 'infinite-scroll', $jetpack_active_modules ) ) {
			return false;
		}
	}
	$nav_class = 'site-navigation paging-navigation';
	if ( is_single() )
		$nav_class = 'site-navigation post-navigation';
	if ( $wp_query->max_num_pages > 1 ) { ?>
        <nav role="navigation" id="<?php echo $nav_id; ?>">
        	<h3 class="assistive-text"><?php _e( 'Post navigation', 'catch-flames' ); ?></h3>
			<?php if ( function_exists('wp_pagenavi' ) )  {
                wp_pagenavi();
            }
            elseif ( function_exists('wp_page_numbers' ) ) {
                wp_page_numbers();
            }
            elseif ( is_search() ) { 
            	//Change Text only for search pages
            	?>
                <div class="nav-previous"><?php next_posts_link( __( '<span class="meta-nav">←</span> NEW Older posts TEXT', 'catch-flames' ) ); ?></div>
                <div class="nav-next"><?php previous_posts_link( __( 'NEW Newer posts TEXT<span class="meta-nav">→</span>', 'catch-flames' ) ); ?></div>
            <?php
            }
            else { ?>
                <div class="nav-previous"><?php next_posts_link( __( '<span class="meta-nav">←</span> Older posts', 'catch-flames' ) ); ?></div>
                <div class="nav-next"><?php previous_posts_link( __( 'Newer posts <span class="meta-nav">→</span>', 'catch-flames' ) ); ?></div>
            <?php
            } ?>
        </nav><!-- #nav -->
	<?php
	}
}
Please note the NEW Older posts TEXT and NEW Newer posts TEXT. You can change this text to desired text for your search page.