It is reported, TRON will launch virtual machine on May 25 (UTC+8), mainnet on May 31, token migration on June 21 and the first 27 super representative elections on June 26. With this date approaching, today, Rfinex announced that it would support the TRON blockchain upgrade and token migration. Investors only need to deposit TRX’s ERC-20 tokens to Rfinex before June 24th in 2018 (UTC+8) and will receive the equivalent TRX token after mainnet launch. No transaction is affected during the migration.
Rfinex is committed to trading digital assets in the simplest way, with such main features as: quick deposit and withdrawal and convenient transaction engine; multi-level risk identification control to protect transaction security; provide professional K-line diagram from tradingview; support multiple devices including computers and mobile phones without installation.

Source: https://rfinex.com/notices/96?lang=en

Here is what you should know about TRX migration: https://medium.com/tron-foundation/guide-to-independence-trx-token-migration-269302b6655c