APK size increased from 60mb to 140mb after switching to Unity 5.6

Hi,

After switching from Unity 5.4.2 to Unity 5.6.1p3 my APK size doubled. There is a huge increase in the "File Headers" which is 161.7 mb!! You can see the build log below. What's the problem please?

Build Report
Uncompressed usage by category:
Textures 66.3 mb 25.4%
Meshes 5.0 mb 1.9%
Animations 0.0 kb 0.0%
Sounds 4.7 mb 1.8%
Shaders 6.7 mb 2.6%
Other Assets 708.9 kb 0.3%
Levels 10.5 mb 4.0%
Scripts 1.4 mb 0.5%
Included DLLs 4.1 mb 1.6%
File headers 161.7 mb 62.0%
Complete size 261.0 mb 100.0%

 

I think it was due to my lightmap settings. I have changed some lightmap settings and it's fixed now.
But I don't understand why "File Headers" size increased

 

I am getting the same issue after light baking. Can you please tell me how you resolved this issue.