The latest round of Brexit negotiations kicked off today in Brussels, with just two months to go before October's EU Summit — widely seen as one of the last feasible dates to secure a withdrawal treaty.

Why it matters: Consensus has been reached on about 85% of the deal, per the NYTimes' Steven Erlanger, but several of the most contentious issues, including the Irish border dilemma and the U.K.'s customs and trade relationship with the EU, have yet to be resolved.

What to watch:

• The original idea for an Irish "backstop," which would allow Northern Ireland to remain in the EU's shared "customs union" and "single market," was rejected by the U.K. in July. Thursday's negotiations will focus on finding an alternative solution to prevent a hard border between Northern Ireland and the Republic of Ireland.
• Friday's talks will seek to clarify the nature of the future trade relationship between the EU and the U.K., after Prime Minister Theresa May's "Chequers proposal" to remain in the EU's single market for goods, but not services, was also rejected.
• In response to the stifling of the Chequers plan, Britain's new Foreign Secretary, Jeremy Hunt, has embarked on a tour of European capitals, lobbying the EU for "a change in approach" and warning of the severe market impact of a "no deal" Brexit.
• The EU's Brexit negotiators reportedly fear that the British secret service has bugged their devices, according to The Telegraph. Regardless of whether that's true, the accusations themselves are a grim indication of the tensions between the negotiating parties.

Go deeper: The U.K. is changing its mind on Brexit.