The U.S. has finally completed a 2011 effort to upgrade the JCREW (Joint Counter Radio-Controlled Improvised Explosive Device Electronic Warfare) jammers used to disable IEDs (improvised explosive devices) detonated wirelessly. Another update was underway but was delayed six years because, well, because of a lot of things.
In 2011 JCREW 3.1 had been a big success because you could easily add new frequencies to jam and was available in several versions. This included one that could be carried by foot patrols. But over the next two years there was no success completing and delivering JCREW 3.3. The situation was so bad that the project was assigned to another company. By 2017 that second development effort apparently succeeded and JCREW 3.3 went into production. Details of what caused the delays is kept secret as are details of how 3.3 works internally. This is standard for electronic weapons that the enemy is constantly trying to duplicate or work around. All that is known about 3.3 is that it is even easier and quicker to be upgrade to add or delete frequencies as well exactly when certain frequencies are employed.
JCREW 3.1 arrived in 2011 after the United States had spent eight years (since 2003) and $17 billion to reduce the effectiveness of IEDs, especially roadside bombs. By 2011 that effort could be considered a qualified success but the enemy kept adapting so IEDs still inflicted casualties.
Source: Strategy Page