Easily solved: When writing an abstraction, document with a date the reason for the abstraction.
Seriously, a comment that goes like this:
"2009 sept 20 : Peter Pan: this abstraction is to hid the ugliness of using SQL Server 2003 which is still in use by Slow Corp."
... now in 2016 a maintainer knows the assumptions and the reasons for the abstractions and can make a much clearer decision about how the abstraction should be treated.
Seriously, a comment that goes like this:
"2009 sept 20 : Peter Pan: this abstraction is to hid the ugliness of using SQL Server 2003 which is still in use by Slow Corp."
... now in 2016 a maintainer knows the assumptions and the reasons for the abstractions and can make a much clearer decision about how the abstraction should be treated.