March 2021 -- The latest attack by the "Houthi" on the ARAMCO oil refinery in Ras Tanura with a swarm of Samad-3 UAV's and other vehicles illustrates that the location of the launch base is in question. The range of the Samad-3 was increased to around 1500 km by an additional fuel-tank, but that does not explain why the "escort" with a significantly shorter range reached the target area (and all went unnoticed, although a flight from Yemen would have taken several hours?).
On March 19, another swarm of "Houthi" drones hit the Riyadh refinery.

Devastating cruise missile attacks on ARAMCO's oil refineries in Saudi-Arabia

2020, February -- Latest analysis of the remains of the Quds missiles show that the engines used are not the original TJ-100, but brand new replica of this; by an unknown manufacturer, and is called T10S.

2019, September 24 -- Following the US, now Britain, France and Germany declare in an official statement that Iran is responsible for the rocket attacks on the Saudi Arabian oil infrastructure.
Comment: Ignorance does not protect against stupidity.

2019, September 18 -- Saudi Arabia defence ministry holds news conference
The ministry display debris of cruise missiles and UAV's that were used on recent attack against the ARAMCO infrastructures. These debris should prove that Iran was the aggressor.
The cruise missile debris, however, come clearly from Yemeni "Quds"with its characteristic fins. The engine matches the Quds's Czech-designed TJ-100 engine pretty well. Also identified UAV's are in the arsenal of the Yemeni rebels. Weapons experts say that
serial numbers on some of the missiles used by the Yemeni Houthi rebels in past attacks and claim that their Iranian origin is proven.
Comment: What a nonsense, serial numbers prove nothing and certainly not that Iran has carried out the attack.

Saudi Arabia defence ministry conference

Other remnants of previous cruise missile attacks prove that they are not "Ya-Ali" CM's

2019, September 18 -- In an official memo to the U.S. embassy in Switzerland, Iran states that the ARAMCO event is not Iran's work. Iran will react against any U.S. action against the country.

2019, September 17 --
Washington wants to present evidence to the attacks next week on the sidelines of the UN general assembly debate in New York. US investigators want to investigate missile parts that were recovered after strikes. The Saudis allegedly have recovered pristine circuit boards from one of the cruise missiles that fell short of its target, provide the specialists the possibility of tracing the missileís point of origin. We are curious to see what for fakes presented there again.

2019, September 16
-- Yemen's Army spokesman, Brigadier General Yahya Sare'e, said in a interview that a different type of engines, something between regular and new type of jet engines were used in Yemeni drones (and cruise missiles) that were involved in a massive and precise raid on Saudi Aramco oil facilities.

2019, September 14 -- On this day, the warlike conflict between Saudi Arabia and the Yemeni Houthi rebels has reached another stage of escalation. A number of drones and cruise missiles of the type "Quds" have caused considerable damage to Khurais oilfield as well as the Abqaiq refinery of ARAMCO in Saudi Arabia. This is after the occasional attacks among other things with the "Burkan" rockets a new quality.
The Houthi rebels have confirmed there attack, but the US administration makes again Iran responsible and announces consequences. It is evidently contemplated, in turn, to destroy Iranian oil refineries.
Iran denies its involvement in the attack of cruise missiles and threatens as well. Amir Ali Hadschisadeh, Commander of the Iranian Revolutionary Guard Air Force, "reminded Washington" that all American bases and their aircraft carriers are within range of its missiles at a distance of up to 2000 kilometers.

Conclusion: The US and Iran are heading back to a military conflict.

It is crazy, but we should ask ourselves if there is an unknown potent sponsor (not Iran) who is conducting a private war against the regime in Saudi Arabia. The Houthi rebels that came out of nowhere would be quasi a private force, and the ever-accumulating and improving rocket technology would have been shopped, certainly not just from Iran.
This is in line with a statement by Houthi General Sare'e, made in a video, that the operation was carried out with the help of "Honorable and Free People in the Kingdom". This could be an indication that the operation was started on Saudi Arabian territory. If drones were involved in the complex attack, then is it possible. Drones have a limited range. In addition, some damages to the infrastructure are so strange that we have to assume that they were caused from close range.
After all cruise missile attacks clearly parts of "Quds" cruise missiles were found. "Quds" have a range of about 700km. This is not enough to reach from the Houthi territory the targets in the center of Saudi Arabia. Since the "Quds" are not of Iranian origin, they were not started from there either. This gives the legitimate assumption that the Houthis (or allies) started them from Saudi Arabian territory.

The Saudis are at a loss, and the U.S. administration is blind in their vicious efforts to inflict damage on Iran.

Here is an excellent article (shortened) stating that the Quds missiles are not of Iranian design, such as Soumar or Hoveizeh:
Fabian Hinz
September 15, 2019

"On September 14, several explosions rocked the Khurais oilfield as well as the Abqaiq refinery, one of Saudi Arabiaís most vital petrochemical installations. Several hours later, the Houthis claimed that they had targeted both facilities with ten drones as part of their ďBalance of DeterrenceĒ campaign.
Indeed, Aramco came to the conclusion that its facilities were attacked by missiles. Even more curious, several pictures began to emerge on social media purportedly showing the wreckage of a missile in the Saudi desert. While the images appear real, neither the date the photos were taken nor their location can be verified. Social media users quickly claimed the images showed a crashed Iranian-made Soumar cruise missile. The Soumar and its updated version, the Hoveizeh, are Iranís attempts at reverse-engineering the Soviet-designed KH-55 cruise missile, several of which the country illegally imported from Ukraine in the early 2000s. Others claimed it was the Quds 1, a recently unveiled Houthi cruise missile often claimed to be a rebranded Soumar.

While at this point there are still more questions about the attack than answers, it might be a good idea to take a closer look at the Quds 1. Do the pictures in the desert actually show a Quds 1? And is the Quds 1 really just a smuggled Soumar?
In early July, the Houthis opened a large static display of their ballistic missile and drone arsenal. One of the surprises unveiled at the show was a cruise missile named Quds 1 which the Houthis claimed to have indigenously developed.

Differences between the Quds 1 and the Soumar include the entire booster design, the wing position, the Quds 1ís fixed wings, the shape of the nose cone, the shape of the aft fuselage, the position of the stabilizers and the shape of the engine cover and exhaust.
The differences in the shape of the aft fuselage and the position of the stabilizers make it clear that the wreckage in the desert is much more likely to be a Quds 1 than a Soumar.
There is yet another apparent difference between the Quds 1 and the Soumar/Hoveizeh: size. A quick measurement using MK1 Eyeball reveals that the Quds 1 seems to be smaller in diameter than the Soumar".
But while MK1 Eyeball works fine, measuring is always a little more objective. So letís go back to the Saudi presentation for a second. When describing the remnants of the alleged Ya-Ali that hit Abha airport, the Saudis mentioned that among the wreckage they found a jet engine named TJ-100.
A quick search reveals that there indeed is a small turbojet engine called TJ-100. The engine is produced by the Czech company PBS Aerospace which describes it as being especially suitable for applications in UAVs, one of its uses being the Spanish/Brazilian Diana target drone.
When comparing the engine seen on the Quds 1 and the TJ-100 it seems pretty clear that whatever powers the Quds 1 is either a TJ-100 or pretty much an exact copy of it. An engine displayed at an Iranian drone exhibition again shows stunning similarities with the TJ-100, implying that Iran is producing a copy of the Czech engine for use in some of its drones.
Knowing the dimensions of the TJ-100, one can precisely measure the diameter of the Quds 1. With 34cm it is significantly smaller than the Soumar, which retains the original KH-55ís diameter of 51.4cm.
However, the Qud 1ís use of a TJ-100 is interesting for more reasons than just measurements. First, the fact that the Quds 1 uses the same engine type that was found in Abha makes it highly likely that the missile that hit Abhaís terminal was a Quds 1 simply mislabeled by Saudi Arabia. The Quds 1ís design also corresponds to the rounded wing and stabilizers found at the scene.
Second, knowing more details about the engine gives us some insights into the performance of the missile. Both the KH-55 and the Soumar use fuel efficient turbofan engines. The TJ-100 however not only has much lower thrust than the original KH-55 engine but also is just your regular old turbojet. This leads to some questions about range. Both the missileís smaller size and its more fuel-hungry engine make it seem unlikely itís range would be anywhere close to the the Soumarís/Hoveizehís range of  1350km."