The KE4 forged iron came out in 2012 and had a 3 year run through 2015. That’s an excellent life span for a new model. Like any of our models, we hate to discontinue, but the market dictates they want “new” models and when we develop new ones, others have to go. W evaluate sales and usually will decide to discontinue a model if we start to see the sales slip. That is not always the case. the sales did not drop off much with the KE4 forged in the 3rd year, but we with other models coming online, we had to reduce the number of models we had. It’s still a great iron and one of my sons still play it.
The current KE4 Tour is probably the most similar in the KE4 family, and has a higher playability (MPF rating). It is a little different profile, meaning the shape is slightly different, but it does have the single weight adjustability that the KE4 Forged had. The current STi iron does not have the adjustable weight, but would be similar in playability. Also a little different profile as well.
Don’t think you can go wrong with either one, or any other models in our line. Also, nothing wrong with continuing to play the KE4 Forged if they are still in good shape.