Android build error when adding appodeal

I have the same problem as the original problem, it doesn’t work when I try to compile on Android.
First I had
“Can’t process class [java/text/CollationElementIterator.class] (Unsupported class version number [52.0] (maximum 51.0, Java 1.7)”. So I have upgraded proguard because apparently the previous version couldn’t be used with java 1.8, and now I have the original error:

 [proguard] Note: there were 8 references to unknown classes.
 [proguard]       You should check your configuration for typos.
 [proguard]       (http://proguard.sourceforge.net/manual/troubleshooting.html#unknownclass)
 [proguard] Note: there were 42 unkept descriptor classes in kept class members.
 [proguard]       You should consider explicitly keeping the mentioned classes
 [proguard]       (using '-keep').
 [proguard]       (http://proguard.sourceforge.net/manual/troubleshooting.html#descriptorclass)
 [proguard] Note: there were 2 unresolved dynamic references to classes or interfaces.
 [proguard]       You should check if you need to specify additional program jars.
 [proguard]       (http://proguard.sourceforge.net/manual/troubleshooting.html#dynamicalclass)
 [proguard] Warning: there were 62 unresolved references to classes or interfaces.
 [proguard]          You may need to add missing library jars or update their versions.
 [proguard]          If your code works fine without the missing classes, you can suppress
 [proguard]          the warnings with '-dontwarn' options.
 [proguard]          (http://proguard.sourceforge.net/manual/troubleshooting.html#unresolvedclass)
BUILD FAILED
C:\ProgrammePerso\Programmation\AndroidSDK\tools\ant\build.xml:597: The following error occurred while executing this line:
C:\ProgrammePerso\Programmation\AndroidSDK\tools\ant\build.xml:871: Please correct the above warnings first.

Hi,

Did you manage to solve this issue? I’m having the same problem after installing 3 or more SDKs from SDKBOX. Did you use ProGuard, enable multi-dex or any other solution?

Thanks.

I would suggest switching to android studio to solve this issue once for all.
https://developer.android.com/studio/build/multidex.html

This is interesting:

When I build my project the first time, I import all the SDKs I want to use (4 of them) it builds and compiles with no problems.

When I import and implement 1 SDK after every build, it gives the too many calls/limit reached issue when I import a 3rd SDK.