After using Joomla 4 for a recent project, and reading your upgrade notes for Joomla 4 and modules, I can highly recommend and request, please please upgrade this plugin to Joomla 4 compatible, even if you have to start charging for it.
The Joomla 4 plugin for email protecting is very ineffective still after all these years, it doesn't grab text from all other components, only content articles from Joomla and K2 directly.
Your plugin was SO efficient at grabbing any email it found and protecting it, that it grabbed emails from other components like Galleries and SPPageBuilder and many others, VirtueMart, all automatically. Right now Joomlas new plugin won't grab emails from PageBuilder, which means this new project isn't protected.
I would be willing to pay for this plugin going forward if you could make it compatible with v4. Even after all this time Joomla has not figured out this is a need, and they need to make it happen. If you can make it happen with your 3rd party plugin they should be able to.
I will see if I will make Email Protector ready for Joomla 4 after the others are done. So even if I do do it, it will not be very soon.
I recommend you report this as an issue on the Joomla issue tracker.
All they really need to do is change the content plugin to a system plugin, and make the replacements on the final output HTML instead of the individual article texts.
But I am not the person that will do that in Joomla core...
I am also very interested in you releasing a new version of the Email Protector for Joomla 4.
I recently updated from Joomla 3 to Joomla 4, using Helix Ultimate template. The email cloaking does not work with the content displayed by this template. It is ridiculous. It also didn't work before with Joomla 3. I was really grateful when I found your Email protector extension.
I kindly ask you to make a version for Joomla 4. Of course I would also pay for it. I do not see another reasonable solution to cloak the emails without deinstalling the Helix ultimate template.
PS: So yes, the new version will have a Pro version. That means that some functionality in the Joomla 3 Free version will also be removed and only available in a Pro version.
I tried it. It converts the email address into images, yes, but every part of the email address is being displayed among each other. Just have a look at the website, that I told you before.
No idea why a template would set a display:block by default on all images. That prevents you to place images inline (which is default behavior in HTML).
@Peter
finally, you developed the Joomla 4 version (thank you).
1 - I remember that during J4 migration you wrote that this plugin was not useful anymore because the new Joomla one was really good.
Please, What has caused your idea changing ?
2 - Can it run with all Extensions like Solidres, HikaShop, DPCalendar, Community Quiz... etc.?
And/or Is there anything we can check to be sure it is fully compatible?
I just suggested the issue should get reported. Seems like nobody did. Nobody claimed they did.
Answering your other 2 questions:
Yes, the Joomla core email cloaker has improved, making it less likely to break javascript and such.
However, it is still a content plugin. That means it only works in content specifically passed through the content plugins. That is only the case with some components and some modules. So the core email cloaking won't work in other components and modules. And not in email addresses you might place directly into the templates index.php file.
So that was the reason to port Email Protector to Joomla 4, as that DOES work in the entire HTML output of the site.
Is there any "technical" (performance) difference from running the plugin as system plugin instead of as content plugin ?
There could be a small trade-off as the plugin gets called at multiple stages in the rendering process. In practice, it shouldn't be a noticeable difference.
Is there something special that 3rd party Extension owners can do on their components to better work with your plugin ?
If the email addresses appear in the HTML output, Email Protector should be able to do its thing.
Do you have a specific case where you see it not working?