THE Kodi crackdown against add-ons continues with a number of popular download extensions closing down after receiving legal warnings.

The Kodi surge continues without any sign of stopping, as users continue to ditch paid TV services for the online player.

Research has suggested Kodi - which offers access to thousands of channels - is being used in more than five million UK homes.

Kodi software is not illegal, but developers can produce third-party add-ons that provide free access to pirated and illegal content.

These apps allow users to stream premium content, like paid-for sports and movie channels for free.

The illegal add-ons are being targeted by ISP's, government agencies, broadcasters and rights holders.

And now a number of popular Kodi add-ons have decided to shut up shop as the crackdown against online piracy continues.

This week Kodi add-on developer jsergio123 signalled the first blow by, in essence, announcing his retirement.

He tweeted: “Sorry to say but I am stopping all development of the urlresolver, metahandler, and my other add ons.”

TorrentFreak said initial reports indicated jsergio123 was calling time on developing Kodi add-ons off the back of threats from Hollywood.

Soon afterwards it was reported UK-based Kodi add-on developer The_Alpha was also quitting.

TV Add Ons published a leaked letter sent to The_Alpha from the Motion Picture Association (MPA) and the Alliance for Creativity and Entertainment.

The ACE is the world’s most powerful anti-piracy organisation, and members include Netflix, HBO, Sky, Disney and Warner Bros.

The leaked letter said: “This letter is addressed to you by companies of the six-major United States film studios represented by the Motion Picture Association (MPA).

“We are writing to you concerning your development, distribution and/or involvement in the operation of certain third party Kodi add-ons.”

The letter also claims The_Alpha is involved in the popular Colossus add-on repository, which has now shut down.

Around the time the leaked letter was revealed, The_Alpha posted a message on Twitter.

They tweeted: “Sorry support TVA battle charity stuff is over I’ll be donating it soon sorry”.

While in a recent tweet jsergio123 added: “The community needs to support @tvaddonsco legal battle. That’s all I’m going to say.”

Amid these blows to Kodi add-on users, the popular Ares Wizard has also now gone offline.

Ares Wizard was an all-in-one setup for Kodi that automates the installs of add-ons.

The Kodi add-on closures comes in a year where authorities have ramped up their efforts to clamp down on online piracy.

The penalties for online piracy has become more severe this year thanks to the Digital Economy Act becoming Law.

The new law raised the maximum possible sentence for online copyright infringement offences from two to 10 years.

The maximum sentence will only apply to people who commit serious copyright crimes, such as distributing content.

This year popular torrent websites like Kickass Torrents, ExtraTorrent and Torrentz.eu have all shut down as piracy penalties have become more severe.

Speaking to Express.co.uk recently, a FACT spokesperson said: “Recent comments from Judges have confirmed that both selling illicit streaming devices and using one to watch or stream copyrighted content are illegal.

“We feel it is important to focus efforts on educating consumers on the legality surrounding these devices and making them aware of the risk and harm they cause not only to industry and the economy, but potentially to themselves and their family.”

But they added: “Our priority for tackling online piracy is to target those most critical to the supply chain.

“Whether it’s a streaming website, an illicit streaming device seller or someone behind an infringing app or add-on, we focus on those who sell, host or distribute content illegally.

“Whilst end users are not a target, they could get swept up in one of our operations and become part of the whole criminal investigation, which could lead to prosecution alongside the suppliers, retailers and importers.”