[Diff since v1.15.0](v1.15.0...v1.15.1)

**Merged pull requests:**
- fix #1020 (#1021) (@baggepinnen)

**Closed issues:**
- ControlSystems.jl fails to compile (#1020)

[Diff since v1.14.0](v1.14.0...v1.15.0)

- Add Makie recipes

**Merged pull requests:**
- optionally return additional arguments from `lqr` and `kalman` (#994) (@baggepinnen)
- improve robustness of hinfnorm (#1015) (@baggepinnen)
- add a few error hints for factorizations on exotic number types (#1016) (@baggepinnen)
- marginplot to support frequency display in Hertz (#1017) (@baggepinnen)
- Add Makie recipes for all plots (#1018) (@baggepinnen)

**Closed issues:**
- `marginplot` doesn't support the `hz` keyword argument (#827)
- `hinfnorm` failure case (#1014)

[Diff since v1.13.1](v1.13.1...v1.14.0)

**Merged pull requests:**
- add `find_similarity_transform` (#1000) (@baggepinnen)
- fix: handle poor type inference in count_eigval_multiplicity function (#1001) (@baggepinnen)
- handle exotic types in `balance` (#1003) (@baggepinnen)
- use new generic zeros from MatrixPencils (#1004) (@baggepinnen)
- Improve some docstrings (#1005) (@baggepinnen)
- handle MIMO tf feedback and division by converting to ss (#1007) (@baggepinnen)
- handle B matrix with non-full column rank in place (#1009) (@baggepinnen)
- add pole placement example (#1010) (@baggepinnen)
- make place return real matrix when expected (#1011) (@baggepinnen)
- add root-locus methods for matrix gains (#1012) (@baggepinnen)
- move root locus implementation to ControlSystemsBase (#1013) (@baggepinnen)

**Closed issues:**
- Docstring for nyquist uses im as an output argument –> clash with the imaginary unit im (#924)

[Diff since v1.13.0](v1.13.0...v1.13.1)

**Merged pull requests:**
- provide signal names to SimResult plot (#991) (@baggepinnen)
- use adaptive sampling for the frequency grid in bode and nyquist plots (#993) (@baggepinnen)
- add functions relating Ms peak to gain and phase margins (#996) (@baggepinnen)
- fix hover with adaptive sampling nyquist plot (#997) (@baggepinnen)
- move some examples to docstrings (#999) (@baggepinnen)

**Closed issues:**
- Observer with pole placement doesn't work for n=3 (#995)

[Diff since v1.12.0](v1.12.0...v1.13.0)

**Merged pull requests:**
- CompatHelper: bump compat for ForwardDiff to 1, (keep existing compat) (#977) (@github-actions[bot])
- add notes on solving for open loop from closed loop (#985) (@baggepinnen)
- implement `typed_hvcat` for LTI systems (#988) (@baggepinnen)
- Use algorithms for poles and zeros of rational matrices from MatrixPencils.jl (#990) (@baggepinnen)

**Closed issues:**
- Missing details in the docstring for Kalman (#986)
- minreal does not give a minimal realisation (#992)

[Diff since v1.11.2](v1.11.2...v1.12.0)

**Merged pull requests:**
- improve tf2ss conversion (#971) (@baggepinnen)
- use zero computations form MatrixPencils (#972) (@baggepinnen)
- enable `tzeros` for `BigFloat` (#976) (@baggepinnen)
- Bump ImplicitDifferentiation bound + run CompatHelper on subpackages (#980) (@gdalle)
- move phase adjustment to margin from marginplot (#981) (@baggepinnen)
- CompatHelper: add new compat entry for ComponentArrays in [weakdeps] at version 0.15 for package ControlSystemsBase, (keep existing compat) (#984) (@github-actions[bot])

**Closed issues:**
- ML-POSOC: Memory-Limited Partially Observable Stochastic Control and Its Mean-Field Control (#973)
- Q: Marginplot -- gain margin with `setPlotScale("dB")` (#979)

[Diff since v1.11.1](v1.11.1...v1.11.2)

**Merged pull requests:**
- do not promote system type when creating a vector (#958) (@baggepinnen)
- remove some dependencies (#959) (@baggepinnen)
- move DSP to an extension (#960) (@baggepinnen)
- Fix negative phase margin (#962) (@baggepinnen)
- Extend docstring (#963) (@CasBex)
- Export PID conversion functions (#964) (@baggepinnen)
- allow more discretization methods in lsim (#966) (@baggepinnen)
- add backward euler discretization (#967) (@baggepinnen)
- add Padé approximation with different numerator and denominator degree (#968) (@baggepinnen)
- handle phase wrapping in margin (#969) (@baggepinnen)
- tweak computation of integrator excess (#970) (@baggepinnen)

**Closed issues:**
- margin() gives incorrect phase margin for system with negative margin (#961)

[Diff since v1.11.0](v1.11.0...v1.11.1)

**Merged pull requests:**
- add 2DOF pid constructor (#951) (@baggepinnen)
- make `feedback2dof` work for any system type (#952) (@baggepinnen)
- add `filter_order` option to `pid` (#953) (@baggepinnen)
- add support for setting filter damping in `pid` (#954) (@baggepinnen)
- add `bodemag_nohess!` (#955) (@baggepinnen)
- avoid some type issues arising with Symbolics (#956) (@baggepinnen)
- add fast path for kd=0 in pid_2dof (#957) (@baggepinnen)

**Closed issues:**
- Tests for pid_design.jl and discrete.jl (#58)
- ControlSystems + DSP (#92)
- Function tf and ss (#145)
- to_matrix (#224)
- Remove LaTeX in plot recipies (#383)
- Problems with getPhaseTicks and getLogTicks (#435)
- Luenberger/Ackermann pole placement for MIMO systems. (#456)
- Update docs for freqresp (#461)
- Help Request: Time Varying LQR Solution (#463)
- Deprecate `norm`? (#543)
- Remaining uses of plot (#610)
- Building a vector of both continuous and discrete (#665)
- Delay system in feedback path throws a method error (#762)
- LsimWorkspace not working for discrete transfer functions (#833)
- Implement `/\` in terms of `feedback` (#901)

[Diff since v1.10.5](v1.10.5...v1.11.0)

**Merged pull requests:**
- fix #941 (#942) (@baggepinnen)
- add concatenation for SimResult (#945) (@baggepinnen)
- bump compat DSP (#946) (@baggepinnen)
- Add function for stable/unstable decomposition (#947) (@baggepinnen)
- remove use of `Polyester.@batch` due to segfault (#948) (@baggepinnen)
- widen the scope of `ss*mat` method (#949) (@baggepinnen)
- add tools for counting multiple eigvals and adjust bode phase start (#950) (@baggepinnen)

**Closed issues:**
- bode() returns only phases in interval +/- 180° (#422)
- `margin` throws an error when the system has delay (#941)
- augstate function for full-state feedback functionality. (#943)

[Diff since v1.10.4](v1.10.4...v1.10.5)

**Merged pull requests:**
- use eps of correct type in balreal (#927) (@baggepinnen)
- Update `minreal` docstring (#935) (@franckgaga)
- add fix for step with plotx and MIMO systems (#936) (@baggepinnen)
- add functions returning the resolvent of a system (#939) (@baggepinnen)
- bump compat DiffEqCallbacks (#940) (@baggepinnen)

**Closed issues:**
- Revisiting old code: was there ever an `LTISystem` composed type in `ControlSystems.jl`? (#938)