Log4Net today's backup file does not have date in file name - date

Question

Below mentioned Log4Net, having date in file name if date is <= yesterday, however files which are back up today, does not have date in file name.
Is it the specification of Log4Net?
Or
It is because of some setting of Log4Net config file?
File
<?xml version="1.0" encoding="UTF-8"?><configuration>
<log4net>
<logger name="SampleLog">
<level value="FATAL"/>
<level value="ERROR"/>
<level value="WARN"/>
<level value="INFO"/>
<level value="DEBUG"/>
<appender-ref ref="SampleLogFile"/>
</logger>
<appender name="SampleLogFile" type="log4net.Appender.RollingFileAppender">
<file type="log4net.Util.PatternString" value="%property{SampleService}"/>
<appendToFile value="true"/>
<maxSizeRollBackups value="15"/>
<maximumFileSize value="1KB"/>
<rollingStyle value="Composite"/>
<datePattern value="yyyyMMdd"/>
<staticLogFileName value="true"/>
<Encoding value="UTF-8"/>
<layout type="log4net.Layout.PatternLayout">
<!-- %d:DateTime, %t:Thread, %-5p:Categories, %c:LoggerName, %m:Message, %n:line separator-->
<param name="ConversionPattern" value="%p %d{ISO8601} %t %m%n"/>
</layout>
</appender>
</log4net>
</configuration>
File name example :
Application_Sample.log // Currently in progress log
Application_Sample.log.1 // Today's backup
Application_Sample.log20190801.2 // Yesterday's backup

Answer 1

You just specify the rollingStyle as Composite, so RollingFileAppender will roll log files on a date period and within a date period on file size. For each day only the last 10 files of 1MB will be kept. And these rolled files will be named: log.txt.1, log.txt.2, log.txt.3, etc. Youcan find the details via https://logging.apache.org/log4net/release/config-examples.html#RollingFileAppender