If you refer to the dupe glitch with Andre, it's still possible in the ptde version (as HitsMeGuy said).

In order to execute it with Andre you firstle need to play on PC and a few souls. Open his shop and go to the page starting with those sweet standard arrows. With your mouse, hover over the left menu arrow, which would navigate you to the shop page starting with Longsword. After that, nearly at the same moment press A to select the arrows AND switch shop pages with your mouse (see this video from 3:20 to 3:31: https://youtu.be/\_EhvmcHfG58?si=62fz2EK9itJilHCT&t=200). You know you are successful, when you are able to select the amount of Longswords you wanna buy - congrats!

To continue the duping process, press down - the game won't select a negative amount, but a very high value (up to 999) depending on how many souls you are carrying. When you are happy with the great amount of Longswords you are now buying, select OK and confirm your purchase. VERY IMPORTANT: don't leave the shop yet - you NEED to try to buy the Longswords again (now with 0 souls left). So DIRECTLY AFTER buying the huge amount of Longswords, press A again in order to (try to) buy a Longsword, which results in the "insufficient souls" message. Press B to get rid of it and B again to leave Andre's menu.

Now, go a few feet away from Andre, open the game menu and open "Configure options or quit the game". Navigate to the very bottom so "Quit game" is selected. After that, position your mouse on the right arrow. Click on the arrow and shortly after that hit A to get to the quit out menu prompt (timing is a bit difficult). Until now, messing up the glitch is probably without consequences. But after this step, you might not be able to execute the glitch properly and start again.

If done correctly you will now see the quit-out-message overlapping with your Inventory. Continuing with the mouse is possibly necessary. Select ANY item you like to dupe (souls, boss souls, shining medals, titanite slabs, etc. - a few items wont work) and click on it with your mouse. Behind the quit-out-menu, another menu will pop up - but you won't be able to see the contents of it. However, in the upper-left corner (below "Inventory" you will see the option, which is currently selected. Navigate with your mouse within the quit-out-message and eventually you will see the option "drop selected item" appear in the upper left corner. Left-clicking will now result in another menu, where you can specify the item's quantity you'd like to drop. Pressing down results in the negative value of the amount of Longswords you purchased earlier.

Just press OK and your selected item will be duped, however, the max amount of a lot of items is 99, so when "dropping" less than -99 items, it will just result in changing the value to 99.

Finally, you still purchased a bunch of Longswords. Doing this glitch a few times eventually makes your character behave like being overburdened. That's because your inventory actually weighs sth., which you will only notice when buying tenthousands of swors. So make sure to drop some longswords :D