I enabled the compress option in logrotate, so after a while, when I was warned that there was little disk space, I saw that the uncompressed logs, dated months ago, were still in / var / log. Should logrotate not auto-replace? Why when, for example, did syslog.94.gz not delete syslog.94?

This all depends on your logrotate.conf file as well as how you run logrotate. Please share more details about both so that people can evaluate your problem better.

# rotate log files weekly:
daily

# keep 4 weeks worth of backlogs:
rotate 360

# create new (empty) log files after rotating old ones:
create

# uncomment if you want to use the date as a suffix of the rotated file
#dateext

# uncomment this if you want your log files compressed:
compress

# some packages install log rotation information in this directory:
include /etc/logrotate.d

# Rotate /var/log/wtmp:
/var/log/wtmp {
monthly
create 0664 root utmp
minsize 1M
rotate 1
}

# Rotate /var/log/btmp:
/var/log/btmp {
monthly
create 0600 root root
rotate 1
}

compress alone does not delete the files, either the rotate number does this, or maxage. You also can run a post-rotate script which can remove the original logs which were compressed.

I understand, as long as there are no 360 files in a given log, the oldest will not be deleted. Counting has resumed on compressed file names, but the date of the logs is sequential.