I have installed IBM iACS 1.1.9.2 on Windows 10.

What are the Java recommendations for this version?
Are there font issues on telnet 5250 if you change your java version?

The getting started guide section on prerequisites simply says java 8 or higher and has some suggested distros of Java
https://www.ibm.com/support/pages/ibm-i-access-acs-getting-started#3.0

The updates page at https://www.ibm.com/support/pages/ibm-i-access-acs-updates also lists some suggested distros of Java but doesn't say what version to use.

To use ACS you need at least the JRE Version 8 on Windows but you can go for higher versions also. 
At the moment I'm running ACS with OpenJDK Version 16.

I haven't noticed any differences between Java 8 and OpenJDK 16.

As far as I understood IBM pointed out under "3.1 Prerequisites (workstation)" that Java 8 is needed to run ACS.

C:\Users\rob>java -version
openjdk version "11.0.12" 2021-07-20
IBM Semeru Runtime Open Edition 11.0.12.0 (build 11.0.12+7)
Eclipse OpenJ9 VM 11.0.12.0 (build openj9-0.27.0, JRE 11 Windows 10 amd64-64-Bit Compressed References 20210730_175 (JIT enabled, AOT enabled)
OpenJ9   - 1851b0074
OMR      - 9db1c870d
JCL      - 21849e2ca0 based on jdk-11.0.12+7)

Looks good! 

My Output looks like this:
java -version
openjdk version "16.0.2" 2021-07-20
OpenJDK Runtime Environment (build 16.0.2+7-67)
OpenJDK 64-Bit Server VM (build 16.0.2+7-67, mixed mode, sharing)

I did click on the feedback on this site and asked for it to be updated for newer versions of iACS and Java
https://www.ibm.com/support/pages/java-options-ibm-i-access-client-solutions

as of today (Tuesday February 13, 2024) this page has NOT been updated.  
https://www.ibm.com/support/pages/java-options-ibm-i-access-client-solutions

Dear Gerald

In my experience, using IBM Semeru JRE for Windows is quite a safe way to go for running IBM i ACS. This can be a reason why the web page you referred to above was no longer updated for a long time now. 

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Chance favors only the prepared mind.
-- Louis Pasteur
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Satid S.
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I have spent hours testing IBM i Access Client Solutions.  Our clients utilize the "PComm Session" font.  We use this font as it scales to fill the monitor, including the left and right margins.  In contrast, the IBM3270 font always maintains a 4:3 aspect ratio and will only scale to a limited size.  Any window beyond that size will simply be filled with black space leaving the 5250 green screen portion relatively small.  When using the IBM3270 font, any version of Java runtime seems to work.  When using the PComm Session font, we cannot proceed beyond Java runtime version 11.  If we do, then the characters on the screen do not align in columns.  For example, a subfile will present a list with the column data shifted left and right.  Also, people report phantom windows where they have 1 session, but they see 3 windows for example.  It is my understanding that the graphics pipeline changed between Java 11 and 17.  I assume that most people are not having an issue because they use the default IBM3270 font that does not scale to large monitors.  However, we are receiving pressure from cybersecurity to move to a newer version of the Java runtime before support runs out.  We currently use the OpenJDK version from Adoptium.