The IRS announced cost-of-living adjustments to many retirement plan limits. The most notable change applies to 401(k) plans. The annual deferral limit increased from $17,500 to $18,000. The catchup contribution for employees aged 50 and over increased from $5500 to $6000. So in 2015, anyone up to age 50 can contribute $18,000 to their 401(k). Anyone age 50 and older can contribute $24,000, $1000 more than in 2014.
You can see all of the 2015 retirement plan contribution limit changes on the IRS website.