From there website (www.stellarterm.com):
StellarTerm is shutting down on September 31 2018.
Development of StellarTerm is unable to keep up with the latest developments of the Stellar network and can't provide the best experience that users all deserve. Unfortunately, due to lack of funding and dev time, StellarTerm will be shutting down.
On September 31 2018, the web app and StellarTerm API will no longer be available. For alternatives, consider checking out Stronghold, stellarx, or the other wallets listed on https://www.stellar.org/lumens/wallets/. StellarTerm is not affiliated with these services.
Thank you for all your support. Onwards.