It seems that Bitmain has taken seriously the issue with their Antminer E3 ASIC miners intended for Ethash stopping to mine Ethereum Classic (ETC) recently and their upcoming inability to mine ETH as well in the very near future. To ensure Bitmain can provide efficient mining equipment for the Ethereum community, it has launched a new firmware to support the Antminer E3. This new firmware has apparently been designed to allow miners to continue using the Antminer E3, even after March 2020. This new firmware addresses the prior issue of the growth of directed acyclic graph (DAG) files, which limited the capability of the Antminer E3s for mining ETH or ETC. This new firmware will expand the usage of Double Date Rate (DDR) Memory, as more space is needed to process DAG files according to the company.
So, how long will the Antminer E3 last with the new firmware? The new firmware has been designed to better support the Antminer E3, and so Bitmain is confident that miners can continue using the hardware past April 2020. With the new firmware update, the final approximate block height of the Antminer E3 is 11,400,000, so according to calculations, mining can continue until October of 2020. ETC mining will stop again earlier than ETH due to the current DAG Epoch for Ethereum Classic being ahead with about 10 Epochs. Regardless, the new DAG size that the E3 miners would be able to handle seems to be increased to 3.97 GB based on the block number data released by Bitmain. So if you have Bitmain Antminer E3 miners you should make sure to update them with the latest firmware released to be able to extend their life to the maximum possible.