chore(deps): update prom/prometheus docker tag to v3.9.1

[renovate]

This PR contains the following updates:

Package	Update	Change
prom/prometheus	minor	v3.8.0 → v3.9.1

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Release Notes

prometheus/prometheus (prom/prometheus)

v3.9.1: 3.9.1 / 2026-01-07

Compare Source

• [BUGFIX] Agent: fix crash shortly after startup from invalid type of object. #​17802
• [BUGFIX] Scraping: fix relabel keep/drop not working. #​17807

v3.9.0: 3.9.0 / 2026-01-06

Compare Source

Note for users of Native Histograms

In version 3.9, Native Histograms is no longer experimental, and the feature flag native-histogram has no effect. You must now turn on
the config setting scrape_native_histograms to collect Native Histogram samples from exporters.

Changelog

• [CHANGE] Native Histograms are no longer experimental! Make the native-histogram feature flag a no-op. Use scrape_native_histograms config option instead. #​17528
• [CHANGE] API: Add maximum limit of 10,000 sets of statistics to TSDB status endpoint. #​17647
• [FEATURE] API: Add /api/v1/features for clients to understand which features are supported. #​17427
• [FEATURE] Promtool: Add start_timestamp field for unit tests. #​17636
• [FEATURE] Promtool: Add --format seriesjson option to tsdb dump to output just series labels in JSON format. #​13409
• [FEATURE] Add --storage.tsdb.delay-compact-file.path flag for better interoperability with Thanos. #​17435
• [FEATURE] UI: Add an option on the query drop-down menu to duplicate that query panel. #​17714
• [ENHANCEMENT]: TSDB: add flag --storage.tsdb.block-reload-interval to configure TSDB Block Reload Interval. #​16728
• [ENHANCEMENT] UI: Add graph option to start the chart's Y axis at zero. #​17565
• [ENHANCEMENT] Scraping: Classic protobuf format no longer requires the unit in the metric name. #​16834
• [ENHANCEMENT] PromQL, Rules, SD, Scraping: Add native histograms to complement existing summaries. #​17374
• [ENHANCEMENT] Notifications: Add a histogram prometheus_notifications_latency_histogram_seconds to complement the existing summary. #​16637
• [ENHANCEMENT] Remote-write: Add custom scope support for AzureAD authentication. #​17483
• [ENHANCEMENT] SD: add a config label with job name for most prometheus_sd_refresh metrics. #​17138
• [ENHANCEMENT] TSDB: New histogram prometheus_tsdb_sample_ooo_delta, the distribution of out-of-order samples in seconds. Collected for all samples, accepted or not. #​17477
• [ENHANCEMENT] Remote-read: Validate histograms received via remote-read. #​17561
• [PERF] TSDB: Small optimizations to postings index. #​17439
• [PERF] Scraping: Speed up relabelling of series. #​17530
• [PERF] PromQL: Small optimisations in binary operators. #​17524, #​17519.
• [BUGFIX] UI: PromQL autocomplete now shows the correct type and HELP text for OpenMetrics counters whose samples end in _total. #​17682
• [BUGFIX] UI: Fixed codemirror-promql incorrectly showing label completion suggestions after the closing curly brace of a vector selector. #​17602
• [BUGFIX] UI: Query editor no longer suggests a duration unit if one is already present after a number. #​17605
• [BUGFIX] PromQL: Fix some "vector cannot contain metrics with the same labelset" errors when experimental delayed name removal is enabled. #​17678
• [BUGFIX] PromQL: Fix possible corruption of PromQL text if the query had an empty ignoring() and non-empty grouping. #​17643
• [BUGFIX] PromQL: Fix resets/changes to return empty results for anchored selectors when all samples are outside the range. #​17479
• [BUGFIX] PromQL: Check more consistently for many-to-one matching in filter binary operators. #​17668
• [BUGFIX] PromQL: Fix collision in unary negation with non-overlapping series. #​17708
• [BUGFIX] PromQL: Fix collision in label_join and label_replace with non-overlapping series. #​17703
• [BUGFIX] PromQL: Fix bug with inconsistent results for queries with OR expression when experimental delayed name removal is enabled. #​17161
• [BUGFIX] PromQL: Ensure that rate/increase/delta of histograms results in a gauge histogram. #​17608
• [BUGFIX] PromQL: Do not panic while iterating over invalid histograms. #​17559
• [BUGFIX] TSDB: Reject chunk files whose encoded chunk length overflows int. #​17533
• [BUGFIX] TSDB: Do not panic during resolution reduction of invalid histograms. #​17561
• [BUGFIX] Remote-write Receive: Avoid duplicate labels when experimental type-and-unit-label feature is enabled. #​17546
• [BUGFIX] OTLP Receiver: Only write metadata to disk when experimental metadata-wal-records feature is enabled. #​17472

v3.8.1: 3.8.1 / 2025-12-16

Compare Source

• [BUGFIX] remote: Fix Remote Write receiver, so it does not send wrong response headers for v1 flow and cause Prometheus senders to emit false partial error log and metrics. #​17683

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Docker Image Vulnerability Report

Tip

Summary: No HIGH/CRITICAL vulnerabilities found across 1 image(s). 🎉

Changed compose files: src/Pi4/docker-compose.yml

New/changed images being scanned:

• prom/prometheus:v3.9.1

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prom/prometheus:v3.9.1

✅ No HIGH or CRITICAL vulnerabilities found.