error: deprecated function in php 7.4 (ubuntu 20.4) with Full-Text RSS 3.8

When I running Full text RSS with PHP7.4 on ubuntu serveur 20.4 (default php version) I have the following text on the XML output :

<b>Deprecated</b>:  The each() function is deprecated. This message will be suppressed on further calls in <b>/web/outils/frss/libraries/Zend/Cache/Backend.php</b> on line <b>79</b><br />
<br />
<b>Deprecated</b>:  implode(): Passing glue string after array is deprecated. Swap the parameters in <b>/web/outils/frss/libraries/simplepie/library/SimplePie/Parse/Date.php</b> on line <b>544</b><br />
<br />
<b>Deprecated</b>:  implode(): Passing glue string after array is deprecated. Swap the parameters in <b>/web/outils/frss/libraries/simplepie/library/SimplePie/Parse/Date.php</b> on line <b>545</b><br />
<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet type="text/xsl" href="css/feed.xsl"?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:media="http://search.yahoo.com/mrss/">
<channel>

And in my RSS reader I have the following error :

fetch error: LibXML error 5 at line 2 (column 1): Extra content at the end of the document

When I install php 7.3 with ppa of Sury it’s working properly (https://launchpad.net/~ondrej/+archive/ubuntu/php)

Is it solved in the last version ?

Hi there,

Yes, the latest version of Full-Text RSS - 3.9.6 - has been tested with PHP 7.4. Earlier versions will produce warnings or errors if run on PHP 7.4. More about version compatibility in our changelog: http://ftr.fivefilters.org/changelog.txt

OK
Apaprently I have also trouble with PHP 7.3 and cache (cf the first line of xml result

<br />
<b>Deprecated</b>:  The each() function is deprecated. This message will be suppressed on further calls in <b>/web/outils/frss/libraries/Zend/Cache/Backend.php</b> on line <b>79</b><br />

Yes, Full-Text RSS 3.8 was released in 2017. It should work with PHP 7.2. If you’re running PHP 7.3 you need at least Full-Text RSS 3.9.5.