The apparently never-ending post-Sandy repair work continues in the 4/5 tunnels connecting Brooklyn and Manhattan all this weekend, so there will be no service in either direction on the 4/5 platforms at Borough Hall from 11:45 PM Friday, June 2 to 5:00 AM Monday, June 5. Fortunately, barring unforeseen circumstances, service on all other lines serving stations in and around Brooklyn Heights should be running normally.
The following work week, Monday, June 5 to Friday, June 9, each night from 11:45 PM to 5:00 AM, there will be no service in either direction at High Street. During those late night hours, A trains will be diverted to the F line, and C trains do not run late at night. All other lines should be running normally.
For planned service changes that may affect travel on other parts of the system, either during the weekend or the following week, see MTA Info or The Weekender.