Status of Authorize.net on Hikashop as of September 2021

My client just created a new Authorize.net account and I went to activate the plugin in Hikashop as I have done for 10 years or so.
Except that it isn't working and upon further research it is due to a change they made some time ago.

The best intel I found so far is to buy a plugin made by a third party. I have no problems with that, but since the MD5 change that precipitated this issue happened 2 years ago, I am wondering why Hikashop didn't rewrite their authorize.net plugin and what the status is at the moment.

For the record, we abandoned Braintree because the Hikashop plugin simply wasn't working. The devs patched it as best they could, but it only worked sometimes and didn't work at all in guest mode.
I am afraid the authorize.net plugin may suffer from the same issue. Can anyone bring me up to date? The Hikashop docs seem to still have the old plugin instruction with the MD5 hash, which I find strange.

Thank you very much.

Thank you for the overview of the authorize.net plugin and its status.
To give you more context, the devs of the Braintree plugin actually updated our plugin and made it work for a time, but there were problems. For instance, the plugin didn't work in Guest mode.
Finally, my client decided to get a authorize.net account.

Because of the unreliable behavior of the braintree plugin I didn't want to update Hikashop, for fear that it would make the patched up plugin stop working altogether.
Consequently, our version of Hikashop was over a year old. Our version is 4.3.0 while the new version is 4.4.3

Yesterday, after trying to make the authorize.net (minus the MD5 field) work, I realized that when selecting it, no credit card screen would show up regardless of the user status (guest, new account or existing user) and the checkout would simply ignore payment and result in an error.
In the authorize.net plugin of version 4.3.0 I did fill the "signature key" I got from authorize.net .

The fields I filled were:
Login ID for Authorize.net
Transaction key for Authorize.net
Authorize Signature Key

But I ignored the MD5 field.

When I tested the site, authorize.net showed up as a choice, but continuing with the checkout I was never presented with a credit card form at all.

At that point I thought that maybe updating Hikashop would also provide me with a new authorize.net plugin that may work. So I did and I installed 4.4.3.

The strange result was that the updated hikashop shop installed fine, but every single product picture went missing. I tried going into a product to restore the image, but there were no images I could choose from in the usual location at all. All products presented the "no image" default image and there was no trace of the original product images.

At that point, I didn't want to leave the live site in those conditions, so I restored the older version with Akeeba and I didn't even look if there was a new authorize.net plugin.

That's where I am now.

My next step is to clone the site in a subdirectory and try again. Yesterday I had no chance to test the new hikashop/authorize.net version because I didn't want a random customer to encounter the messed up website.

Later today, after I clone the website, I am going to have more time to test and see what happened with the images and then I'll test the new authorize plugin (if it indeed exists) with more time to trace both the plugin and the images.

Any idea why updating Hikashop would result in the product images being blasted away?
Is there a new authorize.net plugin with the 4.4.3 version (as I had no chance to even look before I restored the website)?
What else could make the authorize.net plugin display the payment option but then not display the credit card form?

I will update my sandbox results as soon as I can. Thank you.

I have an update on the site. But firsrt I wanted to point out that any forum post dealing with authorize.net and the error I am getting is between 9 and 10 years old. I have a feeling those posts are no longer relevant and I am hesitant to follow those instructions.

After cloning I have had more time to look at why the pictures didn't work.
In the current live site, the images were stored under media/hikashop/upload
The images size was 260 for the category view and 400px for the product page

After the update, somehow the path to the product images changed to images/hikashop/ upload (which I easily fixed)
However, the image size also reverted to 100px for category view and around 150px for product view. That too I fixed
In addition, the modules for "recently viewed" are also showing broken images and a very strange layout.
I am confident I can eventually fix all that.

However, with the authorize.net payment option, after selecting it and clicking "Pay" I get to the confirmation page without seeing any credit card form at all.
If I click on "continue" (or whatever it says, on the checkout, my client made me change it), instead of presenting me with a way to pay, it simply show the error:

(14) The referrer, relay response or receipt link URL is invalid.

I am researching that too, but after the update there are so many things, big and small that don't work properly, I am losing hearth.
I am not sure hw I can fix all those little things on a live site.
Additionally, it's been so long since I built this site, that I don't remember how the Hikashop modules work anymore, as one solution would be to not show "additional products" and "Recently viewed" at least until I can fix them, but the authorize.net issue is the worst, since it was my idea to revert to that as usually it was as simple as entering the proper validation and it would magically work.

I'll keep updating this as aI can.

Last update: I was finally able to reach the authorize.net payment screen. I didn't go any further but it was an improvement over the hell I have been through for the past few hours.

The trick was to regenerate the keys in authorize.net. Once I did that, instead of the two errors I was getting before, I was taken to the Authroize.net payment page.

Still, the process of updating the live site (as opposed to the clone I have been working with so far) is daunting because practically all my image preferences get wiped out, from the size of the images to the location of said images to some of the modules that are broken on certain products but not others.

For instance, some products have broken images in the "recently viewed" module, while in other products they look just fine.
I am exhausted.

Before I go ahead and activate authorize on the main website, I'd like to know why a simple update breaks so many settings vis a vis the images.

But at least authorize.net seems to work.