You can upgrade it if there is a new available firmware update for Dragonmint t1 but if you are planning to upgrade only with Cgminer I think there is no method that you can manually upgrade it. The Cgminer version is depends on the miner's firmware version.
No, it doesn't matter you can still mine with your current cgminer version.
No, According to the quoted below I don't think if halong still active and I'm sure they don't have plan to release a new firmware for t1.
Read this below:
Not surprisingly, following their 'take the money and run' biz plan Halong went out of business at the end of last year and of course ALL of the folks who bought their miners are screwed. Frankly I'm surprised their website is still alive. The only non-scammy and good thing that Halong did was actually deliver the miners before disappearing.
If you having some issue with your current version the only solution you may need for now is to switch to other firmware like Braiin OS.